NetHack guiding candle patch

diff --git c/include/display.h w/include/display.h
index 9da288d..4a1d63b 100644
--- c/include/display.h
+++ w/include/display.h
@@ -59,9 +59,9 @@
  * Infravision is not taken into account.
  */
 #define mon_visible(mon) \
-    (/* The hero can see the monster IF the monster                     */ \
-     (!mon->minvis || See_invisible)  /*     1. is not invisible        */ \
-     && !mon->mundetected             /* AND 2. not an undetected hider */ \
+    (/* The hero can see the monster IF the monster                        */ \
+     (!minvisible(mon) || See_invisible) /*     1. is not invisible        */ \
+     && !mon->mundetected                /* AND 2. not an undetected hider */ \
      && !(mon->mburied || u.uburied)) /* AND 3. neither you nor it is buried */

 /*
@@ -110,7 +110,8 @@
  */
 #define knowninvisible(mon)                                               \
     (mtmp->minvis                                                         \
-     && ((cansee(mon->mx, mon->my) && (See_invisible || Detect_monsters)) \
+     && ((cansee(mon->mx, mon->my) && (See_invisible || Detect_monsters   \
+                                       || candetect(mon->mx, mon->my)))   \
          || (!Blind && (HTelepat & ~INTRINSIC)                            \
              && distu(mon->mx, mon->my) <= (BOLT_LIM * BOLT_LIM))))

diff --git c/include/extern.h w/include/extern.h
index 6959e24..36e7776 100644
--- c/include/extern.h
+++ w/include/extern.h
@@ -275,6 +275,7 @@ E void FDECL(use_crystal_ball, (struct obj **));
 E void NDECL(do_mapping);
 E void FDECL(do_vicinity_map, (struct obj *));
 E void FDECL(cvt_sdoor_to_door, (struct rm *));
+E boolean FDECL(findone_core, (int, int));
 #ifdef USE_TRAMPOLI
 E void FDECL(findone, (int, int, genericptr_t));
 E void FDECL(openone, (int, int, genericptr_t));
@@ -1064,7 +1065,7 @@ E void FDECL(obj_split_light_source, (struct obj *, struct obj *));
 E void FDECL(obj_merge_light_sources, (struct obj *, struct obj *));
 E void FDECL(obj_adjust_light_radius, (struct obj *, int));
 E int FDECL(candle_light_range, (struct obj *));
-E int FDECL(arti_light_radius, (struct obj *));
+E int FDECL(dynamic_light_radius, (struct obj *));
 E const char *FDECL(arti_light_description, (struct obj *));
 E int NDECL(wiz_light_sources);

@@ -1418,6 +1419,7 @@ E void FDECL(setmangry, (struct monst *, BOOLEAN_P));
 E void FDECL(wakeup, (struct monst *, BOOLEAN_P));
 E void NDECL(wake_nearby);
 E void FDECL(wake_nearto, (int, int, int));
+E void FDECL(seemimic_noredraw, (struct monst *));
 E void FDECL(seemimic, (struct monst *));
 E void NDECL(rescham);
 E void NDECL(restartcham);
diff --git c/include/mkroom.h w/include/mkroom.h
index 9d72455..df6a0f7 100644
--- c/include/mkroom.h
+++ w/include/mkroom.h
@@ -34,7 +34,7 @@ struct shclass {
     struct itp {
         int iprob; /* probability of an item type */
         int itype; /* item type: if >=0 a class, if < 0 a specific item */
-    } iprobs[6];
+    } iprobs[7];
     const char *const *shknms; /* list of shopkeeper names for this type */
 };

diff --git c/include/mondata.h w/include/mondata.h
index 41b5f70..f96d574 100644
--- c/include/mondata.h
+++ w/include/mondata.h
@@ -75,6 +75,7 @@
     (lays_eggs(ptr) && (ptr)->mlet == S_EEL && is_swimmer(ptr))
 #define regenerates(ptr) (((ptr)->mflags1 & M1_REGEN) != 0L)
 #define perceives(ptr) (((ptr)->mflags1 & M1_SEE_INVIS) != 0L)
+#define perceives_you(ptr) (perceives(ptr) || candetect(u.ux, u.uy))
 #define can_teleport(ptr) (((ptr)->mflags1 & M1_TPORT) != 0L)
 #define control_teleport(ptr) (((ptr)->mflags1 & M1_TPORT_CNTRL) != 0L)
 #define telepathic(ptr)                                                \
diff --git c/include/monst.h w/include/monst.h
index f9be37f..4882176 100644
--- c/include/monst.h
+++ w/include/monst.h
@@ -174,6 +174,9 @@ struct monst {
     ((mon)->cham == PM_VAMPIRE || (mon)->cham == PM_VAMPIRE_LORD \
      || (mon)->cham == PM_VLAD_THE_IMPALER)

+/* guiding candle makes monsters effectively visible */
+#define minvisible(mon) ((mon)->minvis && !candetect((mon)->mx, (mon)->my))
+
 /* mimic appearances that block vision/light */
 #define is_lightblocker_mappear(mon)                       \
     (is_obj_mappear(mon, BOULDER)                          \
diff --git c/include/obj.h w/include/obj.h
index 62e20b7..6796141 100644
--- c/include/obj.h
+++ w/include/obj.h
@@ -302,7 +302,9 @@ struct obj {

 /* Light sources */
 #define Is_candle(otmp) \
-    (otmp->otyp == TALLOW_CANDLE || otmp->otyp == WAX_CANDLE)
+    (otmp->otyp == TALLOW_CANDLE || otmp->otyp == WAX_CANDLE \
+     || otmp->otyp == GUIDING_CANDLE)
+#define candle_burn_time(otmp) ((otmp)->otyp == TALLOW_CANDLE ? 200L : 400L)
 #define MAX_OIL_IN_FLASK 400 /* maximum amount of oil in a potion of oil */

 /* MAGIC_LAMP intentionally excluded below */
diff --git c/include/rm.h w/include/rm.h
index d6ec078..07676fe 100644
--- c/include/rm.h
+++ w/include/rm.h
@@ -388,6 +388,16 @@ extern struct symsetentry symset[NUM_GRAPHICS]; /* from drawing.c */
 #define W_NONDIGGABLE 0x08
 #define W_NONPASSWALL 0x10

+/*
+ * Filled trapdoors in the Castle can be dug out again.
+ * Conflicts with W_NONPASSWALL above, but Castle has no
+ * non-passwall walls anyway, much less those that can be dug.
+ */
+
+#define FL_DIGGABLE 0x10
+#define Can_dig_hole(x,y,z) (Can_dig_down(z) || Can_fall_thru(z)             \
+                             && (level.locations[x][y].flags & FL_DIGGABLE))
+
 /*
  * Ladders (in Vlad's tower) may be up or down.
  */
@@ -419,7 +429,7 @@ struct rm {

     Bitfield(roomno, 6); /* room # for special rooms */
     Bitfield(edge, 1);   /* marks boundaries for special rooms*/
-    Bitfield(candig, 1); /* Exception to Can_dig_down; was a trapdoor */
+    Bitfield(buried, 1); /* true iff there are buried objects here */
 };

 #define SET_TYPLIT(x, y, ttyp, llit)                              \
diff --git c/include/vision.h w/include/vision.h
index 562f542..5cb5aec 100644
--- c/include/vision.h
+++ w/include/vision.h
@@ -11,15 +11,17 @@ extern char **viz_array;        /* could see/in sight row pointers */
 extern char *viz_rmin;         /* min could see indices */
 extern char *viz_rmax;         /* max could see indices */
 #endif
-#define COULD_SEE 0x1 /* location could be seen, if it were lit */
-#define IN_SIGHT 0x2  /* location can be seen */
-#define TEMP_LIT 0x4  /* location is temporarily lit */
+#define COULD_SEE 0x1   /* location could be seen, if it were lit */
+#define IN_SIGHT 0x2    /* location can be seen */
+#define TEMP_LIT 0x4    /* location is temporarily lit */
+#define TEMP_DETECT 0x8 /* lit by a guiding candle */

 /*
  * Light source sources
  */
 #define LS_OBJECT 0
 #define LS_MONSTER 1
+#define LS_DETECT 2  /* guiding candle */

 /*
  *  cansee()   - Returns true if the hero can see the location.
@@ -30,6 +32,7 @@ extern char *viz_rmax;            /* max could see indices */
 #define cansee(x, y) (viz_array[y][x] & IN_SIGHT)
 #define couldsee(x, y) (viz_array[y][x] & COULD_SEE)
 #define templit(x, y) (viz_array[y][x] & TEMP_LIT)
+#define candetect(x, y) (viz_array[y][x] & TEMP_DETECT)

 /*
  *  The following assume the monster is not blind.
@@ -44,7 +47,7 @@ extern char *viz_rmax;            /* max could see indices */
 #define m_cansee(mtmp, x2, y2) clear_path((mtmp)->mx, (mtmp)->my, (x2), (y2))

 #define m_canseeu(m)                                       \
-    ((!Invis || perceives((m)->data))                      \
+    ((!Invis || perceives_you((m)->data))                  \
              && !(Underwater || u.uburied || (m)->mburied) \
          ? couldsee((m)->mx, (m)->my)                      \
          : 0)
diff --git c/include/youprop.h w/include/youprop.h
index c0eb10e..32b75ae 100644
--- c/include/youprop.h
+++ w/include/youprop.h
@@ -177,7 +177,7 @@
 #define EInvis u.uprops[INVIS].extrinsic
 #define BInvis u.uprops[INVIS].blocked
 #define Invis ((HInvis || EInvis) && !BInvis)
-#define Invisible (Invis && !See_invisible)
+#define Invisible (Invis && !See_invisible && !candetect(u.ux, u.uy))
 /* Note: invisibility also hides inventory and steed */

 #define EDisplaced u.uprops[DISPLACED].extrinsic
diff --git c/src/apply.c w/src/apply.c
index 998d4dd..541ccd6 100644
--- c/src/apply.c
+++ w/src/apply.c
@@ -816,11 +816,11 @@ struct obj *obj;
     struct monst *mtmp;
     unsigned how_seen;
     char mlet;
-    boolean vis, invis_mirror, useeit, monable;
+    boolean vis, invis_mirror, useeit, mcanseeself, monable;

     if (!getdir((char *) 0))
         return 0;
-    invis_mirror = Invis;
+    invis_mirror = Invis && !candetect(u.ux, u.uy);
     useeit = !Blind && (!invis_mirror || See_invisible);
     uvisage = beautiful();
     mirror = simpleonames(obj); /* "mirror" or "looking glass" */
@@ -895,7 +895,7 @@ struct obj *obj;
 #define SEENMON (MONSEEN_NORMAL | MONSEEN_SEEINVIS | MONSEEN_INFRAVIS)
     how_seen = vis ? howmonseen(mtmp) : 0;
     /* whether monster is able to use its vision-based capabilities */
-    monable = !mtmp->mcan && (!mtmp->minvis || perceives(mtmp->data));
+    monable = !mtmp->mcan && (!minvisible(mtmp) || perceives(mtmp->data));
     mlet = mtmp->data->mlet;
     if (mtmp->msleeping) {
         if (vis)
@@ -952,7 +952,7 @@ struct obj *obj;
         if (!tele_restrict(mtmp))
             (void) rloc(mtmp, TRUE);
     } else if (!is_unicorn(mtmp->data) && !humanoid(mtmp->data)
-               && (!mtmp->minvis || perceives(mtmp->data)) && rn2(5)) {
+               && (!minvisible(mtmp) || perceives(mtmp->data)) && rn2(5)) {
         boolean do_react = TRUE;

         if (mtmp->mfrozen) {
@@ -968,9 +968,9 @@ struct obj *obj;
             monflee(mtmp, d(2, 4), FALSE, FALSE);
         }
     } else if (!Blind) {
-        if (mtmp->minvis && !See_invisible)
+        if (minvisible(mtmp) && !See_invisible)
             ;
-        else if ((mtmp->minvis && !perceives(mtmp->data))
+        else if ((minvisible(mtmp) && !perceives(mtmp->data))
                  /* redundant: can't get here if these are true */
                  || !haseyes(mtmp->data) || notonhead || !mtmp->mcansee)
             pline("%s doesn't seem to notice %s reflection.", Monnam(mtmp),
@@ -1208,6 +1208,9 @@ struct obj **optr;
             *optr = 0;
         You("attach %ld%s %s to %s.", obj->quan, !otmp->spe ? "" : " more", s,
             the(xname(otmp)));
+        if (objects[obj->otyp].oc_magic) /* hello SLASH'EM */
+            pline("%s very ordinary.", (obj->quan > 1L) ? "They look"
+                                                        : "It looks");
         if (!otmp->spe || otmp->age > obj->age)
             otmp->age = obj->age;
         otmp->spe += (int) obj->quan;
@@ -1365,7 +1368,7 @@ struct obj *obj;
             pline("%s flame%s %s%s", s_suffix(Yname2(obj)), plur(obj->quan),
                   otense(obj, "burn"), Blind ? "." : " brightly!");
             if (obj->unpaid && costly_spot(u.ux, u.uy)
-                && obj->age == 20L * (long) objects[obj->otyp].oc_cost) {
+                && obj->age == candle_burn_time(obj)) {
                 const char *ithem = (obj->quan > 1L) ? "them" : "it";

                 verbalize("You burn %s, you bought %s!", ithem, ithem);
@@ -2107,7 +2110,7 @@ long timeout;
         /* [m_monnam() yields accurate mon type, overriding hallucination] */
         Sprintf(monnambuf, "%s", an(m_monnam(mtmp)));
         and_vanish[0] = '\0';
-        if ((mtmp->minvis && !See_invisible)
+        if ((minvisible(mtmp) && !See_invisible)
             || (mtmp->data->mlet == S_MIMIC
                 && M_AP_TYPE(mtmp) != M_AP_NOTHING))
             suppress_see = TRUE;
@@ -3402,8 +3405,7 @@ struct obj *obj;
                     fillmsg = TRUE;
                 } else
                     digactualhole(x, y, BY_OBJECT, (rn2(obj->spe) < 3
-                                                    || (!Can_dig_down(&u.uz)
-                                                        && !levl[x][y].candig))
+                                                 || !Can_dig_hole(x, y, &u.uz))
                                                       ? PIT
                                                       : HOLE);
             }
@@ -3652,6 +3654,7 @@ doapply()
         break;
     case WAX_CANDLE:
     case TALLOW_CANDLE:
+    case GUIDING_CANDLE:
         use_candle(&obj);
         break;
     case OIL_LAMP:
diff --git c/src/detect.c w/src/detect.c
index 4527168..c2a4803 100644
--- c/src/detect.c
+++ w/src/detect.c
@@ -1443,46 +1443,59 @@ struct rm *lev;
     lev->doormask = newmask;
 }

-STATIC_PTR void
-findone(zx, zy, num)
+/* also used in display.c */
+boolean
+findone_core(zx, zy)
 int zx, zy;
-genericptr_t num;
 {
     register struct trap *ttmp;
     register struct monst *mtmp;
+    boolean result = FALSE;

     if (levl[zx][zy].typ == SDOOR) {
         cvt_sdoor_to_door(&levl[zx][zy]); /* .typ = DOOR */
         magic_map_background(zx, zy, 0);
-        newsym(zx, zy);
-        (*(int *) num)++;
-    } else if (levl[zx][zy].typ == SCORR) {
+        return TRUE;
+    }
+    if (levl[zx][zy].typ == SCORR) {
         levl[zx][zy].typ = CORR;
         unblock_point(zx, zy);
         magic_map_background(zx, zy, 0);
-        newsym(zx, zy);
-        (*(int *) num)++;
-    } else if ((ttmp = t_at(zx, zy)) != 0) {
+        return TRUE;
+    }
+    if ((ttmp = t_at(zx, zy)) != 0) {
         if (!ttmp->tseen && ttmp->ttyp != STATUE_TRAP) {
             ttmp->tseen = 1;
-            newsym(zx, zy);
-            (*(int *) num)++;
+            return TRUE;
         }
-    } else if ((mtmp = m_at(zx, zy)) != 0) {
+    }
+    if ((mtmp = m_at(zx, zy)) != 0) {
         if (M_AP_TYPE(mtmp)) {
-            seemimic(mtmp);
-            (*(int *) num)++;
+            seemimic_noredraw(mtmp);
+            result = TRUE;
         }
         if (mtmp->mundetected
             && (is_hider(mtmp->data) || mtmp->data->mlet == S_EEL)) {
             mtmp->mundetected = 0;
-            newsym(zx, zy);
-            (*(int *) num)++;
+            result = TRUE;
         }
         if (!canspotmon(mtmp) && !glyph_is_invisible(levl[zx][zy].glyph))
             map_invisible(zx, zy);
-    } else if (unmap_invisible(zx, zy)) {
+    } else if (glyph_is_invisible(levl[zx][zy].glyph)) {
+        unmap_object(zx, zy);
+        result = TRUE;
+    }
+    return result;
+}
+
+STATIC_PTR void
+findone(zx, zy, num)
+int zx, zy;
+genericptr_t num;
+{
+    if (findone_core(zx, zy)) {
         (*(int *) num)++;
+        newsym(zx, zy);
     }
 }

diff --git c/src/dig.c w/src/dig.c
index dbf5eb5..d44ea1f 100644
--- c/src/dig.c
+++ w/src/dig.c
@@ -219,7 +219,7 @@ int x, y;
                || (ttmp
                    && (ttmp->ttyp == MAGIC_PORTAL
                        || ttmp->ttyp == VIBRATING_SQUARE
-                       || (!Can_dig_down(&u.uz) && !levl[x][y].candig)))) {
+                       || !Can_dig_hole(x, y, &u.uz)))) {
         if (verbose)
             pline_The("%s here is too hard to %s.", surface(x, y), verb);
         return FALSE;
@@ -579,7 +579,7 @@ int ttyp;
         return;
     }

-    if (ttyp != PIT && (!Can_dig_down(&u.uz) && !lev->candig)) {
+    if (ttyp != PIT && !Can_dig_hole(x, y, &u.uz)) {
         impossible("digactualhole: can't dig %s on this level.",
                    defsyms[trap_to_defsym(ttyp)].explanation);
         ttyp = PIT;
@@ -783,7 +783,7 @@ coord *cc;

     ttmp = t_at(dig_x, dig_y);
     lev = &levl[dig_x][dig_y];
-    nohole = (!Can_dig_down(&u.uz) && !lev->candig);
+    nohole = !Can_dig_hole(dig_x, dig_y, &u.uz);

     if ((ttmp && (ttmp->ttyp == MAGIC_PORTAL
                   || ttmp->ttyp == VIBRATING_SQUARE || nohole))
@@ -866,9 +866,9 @@ coord *cc;
     } else {
         typ = fillholetyp(dig_x, dig_y, FALSE);

-        lev->flags = 0;
         if (typ != ROOM) {
             lev->typ = typ;
+            lev->flags = 0;
             liquid_flow(dig_x, dig_y, typ, ttmp,
                         "As you dig, the hole fills with %s!");
             return TRUE;
@@ -1931,23 +1931,27 @@ int x, y;
     coord cc;

     debugpline2("unearth_objs: at <%d,%d>", x, y);
-    cc.x = x;
-    cc.y = y;
-    bball = buried_ball(&cc);
-    for (otmp = level.buriedobjlist; otmp; otmp = otmp2) {
-        otmp2 = otmp->nobj;
-        if (otmp->ox == x && otmp->oy == y) {
-            if (bball && otmp == bball
-                && u.utrap && u.utraptype == TT_BURIEDBALL) {
-                buried_ball_to_punishment();
-            } else {
-                obj_extract_self(otmp);
-                if (otmp->timed)
-                    (void) stop_timer(ROT_ORGANIC, obj_to_any(otmp));
-                place_object(otmp, x, y);
-                stackobj(otmp);
+
+    if (levl[x][y].buried) {
+        cc.x = x;
+        cc.y = y;
+        bball = buried_ball(&cc);
+        for (otmp = level.buriedobjlist; otmp; otmp = otmp2) {
+            otmp2 = otmp->nobj;
+            if (otmp->ox == x && otmp->oy == y) {
+                if (bball && otmp == bball
+                    && u.utrap && u.utraptype == TT_BURIEDBALL) {
+                    buried_ball_to_punishment();
+                } else {
+                    obj_extract_self(otmp);
+                    if (otmp->timed)
+                        (void) stop_timer(ROT_ORGANIC, obj_to_any(otmp));
+                    place_object(otmp, x, y);
+                    stackobj(otmp);
+                }
             }
         }
+        levl[x][y].buried = 0;
     }
     del_engr_at(x, y);
     newsym(x, y);
diff --git c/src/display.c w/src/display.c
index c5b155b..2ea8b06 100644
--- c/src/display.c
+++ w/src/display.c
@@ -123,6 +123,7 @@
  */
 #include "hack.h"

+STATIC_DCL void FDECL(map_buried, (int, int, int));
 STATIC_DCL void FDECL(display_monster,
                       (XCHAR_P, XCHAR_P, struct monst *, int, XCHAR_P));
 STATIC_DCL int FDECL(swallow_to_glyph, (int, int));
@@ -264,6 +265,26 @@ register int show;
         show_glyph(x, y, glyph);
 }

+/*
+ * map_buried()
+ * Map the object buried under the specified tile.
+ * If there are several, we need to display the very last one
+ * to be consistent with object_detect().
+ */
+
+STATIC_OVL void
+map_buried(x, y, show)
+int x, y;
+int show;
+{
+    struct obj *obj, *last_obj = NULL;
+    for (obj = level.buriedobjlist; obj; obj = obj->nobj)
+        if (obj->ox == x && obj->oy == y)
+            last_obj = obj;
+    if (last_obj)
+        map_object(last_obj, show);
+}
+
 /*
  * map_invisible()
  *
@@ -344,8 +365,11 @@ register int x, y;
         register struct obj *obj;                                           \
         register struct trap *trap;                                         \
                                                                             \
-        if ((obj = vobj_at(x, y)) && !covers_objects(x, y))                 \
+        if ((obj = vobj_at(x, y)) && (!covers_objects(x, y)                 \
+                                      || candetect(x, y) && cansee(x, y)))  \
             map_object(obj, show);                                          \
+        else if (levl[x][y].buried && candetect(x, y) && cansee(x, y))      \
+            map_buried(x, y, show);                                         \
         else if ((trap = t_at(x, y)) && trap->tseen && !covers_traps(x, y)) \
             map_trap(trap, show);                                           \
         else                                                                \
@@ -772,6 +796,10 @@ register int x, y;
             return;
         }

+        /* guiding candle! */
+        if (candetect(x,y))
+            findone_core(x,y);
+
         if (x == u.ux && y == u.uy) {
             int see_self = canspotself();

diff --git c/src/do_name.c w/src/do_name.c
index 6dd8d5a..48921b0 100644
--- c/src/do_name.c
+++ w/src/do_name.c
@@ -1151,7 +1151,7 @@ do_mname()
             && (!(cansee(cx, cy) || see_with_infrared(mtmp))
                 || mtmp->mundetected || M_AP_TYPE(mtmp) == M_AP_FURNITURE
                 || M_AP_TYPE(mtmp) == M_AP_OBJECT
-                || (mtmp->minvis && !See_invisible)))) {
+                || (minvisible(mtmp) && !See_invisible)))) {
         pline("I see no monster there.");
         return;
     }
diff --git c/src/do_wear.c w/src/do_wear.c
index 9132e75..df2de3f 100644
--- c/src/do_wear.c
+++ w/src/do_wear.c
@@ -287,8 +287,9 @@ Cloak_on(VOID_ARGS)
         /* Note: it's already being worn, so we have to cheat here. */
         if ((HInvis || EInvis) && !Blind) {
             newsym(u.ux, u.uy);
-            You("can %s!", See_invisible ? "no longer see through yourself"
-                                         : see_yourself);
+            You("can %s!", See_invisible || candetect(u.ux, u.uy)
+                           ? "no longer see through yourself"
+                           : see_yourself);
         }
         break;
     case CLOAK_OF_INVISIBILITY:
@@ -298,7 +299,7 @@ Cloak_on(VOID_ARGS)
             makeknown(uarmc->otyp);
             newsym(u.ux, u.uy);
             pline("Suddenly you can%s yourself.",
-                  See_invisible ? " see through" : "not see");
+                  !Invisible ? " see through" : "not see");
         }
         break;
     case OILSKIN_CLOAK:
@@ -343,8 +344,8 @@ Cloak_off(VOID_ARGS)
     case MUMMY_WRAPPING:
         if (Invis && !Blind) {
             newsym(u.ux, u.uy);
-            You("can %s.", See_invisible ? "see through yourself"
-                                         : "no longer see yourself");
+            You("can %s.", !Invisible ? "see through yourself"
+                                      : "no longer see yourself");
         }
         break;
     case CLOAK_OF_INVISIBILITY:
@@ -352,8 +353,9 @@ Cloak_off(VOID_ARGS)
             makeknown(CLOAK_OF_INVISIBILITY);
             newsym(u.ux, u.uy);
             pline("Suddenly you can %s.",
-                  See_invisible ? "no longer see through yourself"
-                                : see_yourself);
+                  See_invisible || candetect(u.ux, u.uy)
+                  ? "no longer see through yourself"
+                  : see_yourself);
         }
         break;
     /* Alchemy smock gives poison _and_ acid resistance */
@@ -900,7 +902,8 @@ register struct obj *obj;
         set_mimic_blocking(); /* do special mimic handling */
         see_monsters();

-        if (Invis && !oldprop && !HSee_invisible && !Blind) {
+        if (Invis && !oldprop && !HSee_invisible
+            && !Blind && !candetect(u.ux, u.uy)) {
             newsym(u.ux, u.uy);
             pline("Suddenly you are transparent, but there!");
             learnring(obj, TRUE);
@@ -1024,7 +1027,8 @@ boolean gone;
         if (!Invis && !BInvis && !Blind) {
             newsym(u.ux, u.uy);
             Your("body seems to unfade%s.",
-                 See_invisible ? " completely" : "..");
+                 See_invisible || candetect(u.ux, u.uy) ? " completely"
+                                                        : "..");
             learnring(obj, TRUE);
         }
         break;
diff --git c/src/dogmove.c w/src/dogmove.c
index df3452f..d3e55aa 100644
--- c/src/dogmove.c
+++ w/src/dogmove.c
@@ -649,7 +649,7 @@ int maxdist;

         if ((targ = m_at(curx, cury)) != 0) {
             /* Is the monster visible to the pet? */
-            if ((!targ->minvis || perceives(mtmp->data))
+            if ((!minvisible(targ) || perceives(mtmp->data))
                 && !targ->mundetected)
                 break;
             /* If the pet can't see it, it assumes it aint there */
@@ -692,7 +692,7 @@ int    maxdist;
         if (pal) {
             if (pal->mtame) {
                 /* Pet won't notice invisible pets */
-                if (!pal->minvis || perceives(mtmp->data))
+                if (!minvisible(pal) || perceives(mtmp->data))
                     return 1;
             } else {
                 /* Quest leaders and guardians are always seen */
@@ -1007,7 +1007,7 @@ int after; /* this is extra fast monster movement */
             if ((int) mtmp2->m_lev >= (int) mtmp->m_lev + 2
                 || (mtmp2->data == &mons[PM_FLOATING_EYE] && rn2(10)
                     && mtmp->mcansee && haseyes(mtmp->data) && mtmp2->mcansee
-                    && (perceives(mtmp->data) || !mtmp2->minvis))
+                    && (perceives(mtmp->data) || !minvisible(mtmp2)))
                 || (mtmp2->data == &mons[PM_GELATINOUS_CUBE] && rn2(10))
                 || (max_passive_dmg(mtmp2, mtmp) >= mtmp->mhp)
                 || ((mtmp->mhp * 4 < mtmp->mhpmax
diff --git c/src/eat.c w/src/eat.c
index 4dd3a0a..f3bd5d0 100644
--- c/src/eat.c
+++ w/src/eat.c
@@ -1969,15 +1969,14 @@ struct obj *otmp;
                 set_mimic_blocking();
                 see_monsters();
                 if (Invis && !oldprop && !ESee_invisible
-                    && !perceives(youmonst.data) && !Blind) {
+                    && !perceives_you(youmonst.data) && !Blind) {
                     newsym(u.ux, u.uy);
                     pline("Suddenly you can see yourself.");
                     makeknown(typ);
                 }
                 break;
             case RIN_INVISIBILITY:
-                if (!oldprop && !EInvis && !BInvis && !See_invisible
-                    && !Blind) {
+                if (!oldprop && !EInvis && !BInvis && Invisible && !Blind) {
                     newsym(u.ux, u.uy);
                     Your("body takes on a %s transparency...",
                          Hallucination ? "normal" : "strange");
diff --git c/src/hack.c w/src/hack.c
index d84dd35..4e9d32e 100644
--- c/src/hack.c
+++ w/src/hack.c
@@ -220,8 +220,7 @@ moverock()
                     deltrap(ttmp);
                     delobj(otmp);
                     bury_objs(rx, ry);
-                    levl[rx][ry].wall_info &= ~W_NONDIGGABLE;
-                    levl[rx][ry].candig = 1;
+                    levl[rx][ry].flags |= FL_DIGGABLE;
                     if (cansee(rx, ry))
                         newsym(rx, ry);
                     return sobj_at(BOULDER, sx, sy) ? -1 : 0;
@@ -2657,7 +2656,8 @@ lookaround()
             if ((mtmp = m_at(x, y)) != 0
                 && M_AP_TYPE(mtmp) != M_AP_FURNITURE
                 && M_AP_TYPE(mtmp) != M_AP_OBJECT
-                && (!mtmp->minvis || See_invisible) && !mtmp->mundetected) {
+                && (!minvisible(mtmp) || See_invisible)
+                && !mtmp->mundetected) {
                 if ((context.run != 1 && !mtmp->mtame)
                     || (x == u.ux + u.dx && y == u.uy + u.dy
                         && !context.travel)) {
diff --git c/src/invent.c w/src/invent.c
index ff69de7..b3b675c 100644
--- c/src/invent.c
+++ w/src/invent.c
@@ -4384,6 +4384,9 @@ boolean as_if_seen;
     menu_item *selected = 0;
     int n;

+    if (!levl[x][y].buried)
+        return 0; /* nothing to do here */
+
     /* count # of objects here */
     for (n = 0, obj = level.buriedobjlist; obj; obj = obj->nobj)
         if (obj->ox == x && obj->oy == y) {
diff --git c/src/light.c w/src/light.c
index 446dc39..0c025fa 100644
--- c/src/light.c
+++ w/src/light.c
@@ -41,6 +41,7 @@
 /* flags */
 #define LSF_SHOW 0x1        /* display the light source */
 #define LSF_NEEDS_FIXUP 0x2 /* need oid fixup */
+#define LSF_DETECT 0x4      /* guiding candle */

 static light_source *light_base = 0;

@@ -71,9 +72,9 @@ anything *id;
     ls->x = x;
     ls->y = y;
     ls->range = range;
-    ls->type = type;
+    ls->type = type & ~LS_DETECT;
     ls->id = *id;
-    ls->flags = 0;
+    ls->flags = type & LS_DETECT ? LSF_DETECT : 0;
     light_base = ls;

     vision_full_recalc = 1; /* make the source show up */
@@ -157,9 +158,10 @@ char **cs_rows;
         /* minor optimization: don't bother with duplicate light sources */
         /* at hero */
         if (ls->x == u.ux && ls->y == u.uy) {
-            if (at_hero_range >= ls->range)
-                ls->flags &= ~LSF_SHOW;
-            else
+            if (at_hero_range >= ls->range) {
+                if (!(ls->flags & LSF_DETECT))
+                    ls->flags &= ~LSF_SHOW;
+            } else
                 at_hero_range = ls->range;
         }

@@ -197,13 +199,19 @@ char **cs_rows;
                      * does this.
                      */
                     for (x = min_x; x <= max_x; x++)
-                        if (row[x] & COULD_SEE)
+                        if (row[x] & COULD_SEE) {
                             row[x] |= TEMP_LIT;
+                            if (ls->flags & LSF_DETECT)
+                                row[x] |= TEMP_DETECT;
+                        }
                 } else {
                     for (x = min_x; x <= max_x; x++)
                         if ((ls->x == x && ls->y == y)
-                            || clear_path((int) ls->x, (int) ls->y, x, y))
+                            || clear_path((int) ls->x, (int) ls->y, x, y)) {
                             row[x] |= TEMP_LIT;
+                            if (ls->flags & LSF_DETECT)
+                                row[x] |= TEMP_DETECT;
+                        }
                 }
             }
         }
@@ -602,10 +610,18 @@ struct obj *obj;
 int new_radius;
 {
     light_source *ls;
+    short old_flags;

     for (ls = light_base; ls; ls = ls->next)
         if (ls->type == LS_OBJECT && ls->id.a_obj == obj) {
-            if (new_radius != ls->range)
+            old_flags = ls->flags;
+            if (obj->otyp == GUIDING_CANDLE) {
+                if (obj->cursed)
+                    ls->flags &= ~LSF_DETECT;
+                else
+                    ls->flags |= LSF_DETECT;
+            }
+            if (new_radius != ls->range || ls->flags != old_flags)
                 vision_full_recalc = 1;
             ls->range = new_radius;
             return;
@@ -646,6 +662,8 @@ struct obj *obj;
             radius++;
             n /= 7L;
         } while (n > 0L);
+        if (obj->otyp == GUIDING_CANDLE && obj->blessed)
+            radius++; /* make them less useless in late game */
     } else {
         /* we're only called for lit candelabrum or candles */
         /* impossible("candlelight for %d?", obj->otyp); */
@@ -656,7 +674,7 @@ struct obj *obj;

 /* light emitting artifact's range depends upon its curse/bless state */
 int
-arti_light_radius(obj)
+dynamic_light_radius(obj)
 struct obj *obj;
 {
     /*
@@ -667,9 +685,12 @@ struct obj *obj;
      */

     /* sanity check [simplifies usage by bless()/curse()/&c] */
-    if (!obj->lamplit || !artifact_light(obj))
+    if (!obj->lamplit || !artifact_light(obj) && obj->otyp != GUIDING_CANDLE)
         return 0;

+    if (obj->otyp == GUIDING_CANDLE)
+        return candle_light_range(obj);
+
     /* cursed radius of 1 is not noticeable for an item that's
        carried by the hero but is if it's carried by a monster
        or left lit on the floor (not applicable for Sunsword) */
@@ -681,7 +702,7 @@ const char *
 arti_light_description(obj)
 struct obj *obj;
 {
-    switch (arti_light_radius(obj)) {
+    switch (dynamic_light_radius(obj)) {
     case 3:
         return "brilliantly"; /* blessed */
     case 2:
diff --git c/src/mcastu.c w/src/mcastu.c
index 1f73638..b59981a 100644
--- c/src/mcastu.c
+++ w/src/mcastu.c
@@ -59,7 +59,7 @@ boolean undirected;

         if (undirected)
             point_msg = "all around, then curses";
-        else if ((Invis && !perceives(mtmp->data)
+        else if ((Invis && !perceives_you(mtmp->data)
                   && (mtmp->mux != u.ux || mtmp->muy != u.uy))
                  || is_obj_mappear(&youmonst, STRANGE_OBJECT)
                  || u.uundetected)
@@ -264,7 +264,7 @@ boolean foundyou;
               canspotmon(mtmp) ? Monnam(mtmp) : "Something",
               is_undirected_spell(mattk->adtyp, spellnum)
                   ? ""
-                  : (Invisible && !perceives(mtmp->data)
+                  : (Invis && !perceives_you(mtmp->data)
                      && (mtmp->mux != u.ux || mtmp->muy != u.uy))
                         ? " at a spot near you"
                         : (Displaced
@@ -414,7 +414,7 @@ int spellnum;

             /* messages not quite right if plural monsters created but
                only a single monster is seen */
-            if (Invisible && !perceives(mtmp->data)
+            if (Invis && !perceives_you(mtmp->data)
                 && (mtmp->mux != u.ux || mtmp->muy != u.uy))
                 pline("%s around a spot near you!", mappear);
             else if (Displaced && (mtmp->mux != u.ux || mtmp->muy != u.uy))
@@ -463,7 +463,8 @@ int spellnum;
         if (!mtmp->minvis && !mtmp->invis_blkd) {
             if (canseemon(mtmp))
                 pline("%s suddenly %s!", Monnam(mtmp),
-                      !See_invisible ? "disappears" : "becomes transparent");
+                      !See_invisible && !candetect(mtmp->mx, mtmp->my)
+                      ? "disappears" : "becomes transparent");
             mon_set_minvis(mtmp);
             if (cansee(mtmp->mx, mtmp->my) && !canspotmon(mtmp))
                 map_invisible(mtmp->mx, mtmp->my);
@@ -640,7 +641,7 @@ int spellnum;
             fmt = "%s casts at a clump of sticks, but nothing happens.";
         else if (let == S_SNAKE)
             fmt = "%s transforms a clump of sticks into snakes!";
-        else if (Invisible && !perceives(mtmp->data)
+        else if (Invis && !perceives_you(mtmp->data)
                  && (mtmp->mux != u.ux || mtmp->muy != u.uy))
             fmt = "%s summons insects around a spot near you!";
         else if (Displaced && (mtmp->mux != u.ux || mtmp->muy != u.uy))
diff --git c/src/mhitm.c w/src/mhitm.c
index 79f1e67..2320b2e 100644
--- c/src/mhitm.c
+++ w/src/mhitm.c
@@ -609,7 +609,7 @@ struct attack *mattk;
     }

     if (magr->mcan || !magr->mcansee || !mdef->mcansee
-        || (magr->minvis && !perceives(mdef->data)) || mdef->msleeping) {
+        || (minvisible(magr) && !perceives(mdef->data)) || mdef->msleeping) {
         if (vis && canspotmon(mdef))
             pline("but nothing happens.");
         return MM_MISS;
@@ -625,7 +625,7 @@ struct attack *mattk;
                                       "The gaze is reflected away by %s %s.");
                 return MM_MISS;
             }
-            if (mdef->minvis && !perceives(magr->data)) {
+            if (minvisible(mdef) && !perceives(magr->data)) {
                 if (canseemon(magr)) {
                     pline(
                       "%s doesn't seem to notice that %s gaze was reflected.",
@@ -1590,7 +1590,7 @@ int mdead;
                 if (!rn2(4))
                     tmp = 127;
                 if (magr->mcansee && haseyes(madat) && mdef->mcansee
-                    && (perceives(madat) || !mdef->minvis)) {
+                    && (perceives(madat) || !minvisible(mdef))) {
                     /* construct format string; guard against '%' in Monnam */
                     Strcpy(buf, s_suffix(Monnam(mdef)));
                     (void) strNsubst(buf, "%", "%%", 0);
diff --git c/src/mhitu.c w/src/mhitu.c
index db92458..1927d01 100644
--- c/src/mhitu.c
+++ w/src/mhitu.c
@@ -159,7 +159,7 @@ struct attack *mattk;
               ? could_seduce(mtmp, &youmonst, mattk) : 0);
     Monst_name = Monnam(mtmp);

-    if (!mtmp->mcansee || (Invis && !perceives(mtmp->data))) {
+    if (!mtmp->mcansee || (Invis && !perceives_you(mtmp->data))) {
         const char *swings = (mattk->aatyp == AT_BITE) ? "snaps"
                              : (mattk->aatyp == AT_KICK) ? "kicks"
                                : (mattk->aatyp == AT_STNG
@@ -573,7 +573,7 @@ register struct monst *mtmp;
     tmp += mtmp->m_lev;
     if (multi < 0)
         tmp += 4;
-    if ((Invis && !perceives(mdat)) || !mtmp->mcansee)
+    if ((Invis && !perceives_you(mdat)) || !mtmp->mcansee)
         tmp -= 2;
     if (mtmp->mtrapped)
         tmp -= 2;
@@ -2386,16 +2386,18 @@ struct attack *mattk; /* non-Null: current attack; Null: general capability */
         pagr = youmonst.data;
         agrinvis = (Invis != 0);
         genagr = poly_gender();
+        defperc = candetect(u.ux, u.uy);
     } else {
         pagr = magr->data;
         agrinvis = magr->minvis;
         genagr = gender(magr);
+        defperc = candetect(magr->mx, magr->my);
     }
     if (mdef == &youmonst) {
-        defperc = (See_invisible != 0);
+        defperc = defperc || See_invisible;
         gendef = poly_gender();
     } else {
-        defperc = perceives(mdef->data);
+        defperc = defperc || perceives(mdef->data);
         gendef = gender(mdef);
     }

@@ -2873,7 +2875,7 @@ struct attack *mattk;
                 if (!rn2(4))
                     tmp = 127;
                 if (mtmp->mcansee && haseyes(mtmp->data) && rn2(3)
-                    && (perceives(mtmp->data) || !Invis)) {
+                    && (perceives_you(mtmp->data) || !Invis)) {
                     if (Blind)
                         pline("As a blind %s, you cannot defend yourself.",
                               youmonst.data->mname);
diff --git c/src/mkobj.c w/src/mkobj.c
index 195de0b..1909852 100644
--- c/src/mkobj.c
+++ w/src/mkobj.c
@@ -10,6 +10,7 @@ STATIC_DCL unsigned FDECL(nextoid, (struct obj *, struct obj *));
 STATIC_DCL void FDECL(maybe_adjust_light, (struct obj *, int));
 STATIC_DCL void FDECL(obj_timer_checks, (struct obj *,
                                          XCHAR_P, XCHAR_P, int));
+STATIC_DCL void FDECL(recheck_buried, (int, int));
 STATIC_DCL void FDECL(container_weight, (struct obj *));
 STATIC_DCL struct obj *FDECL(save_mtraits, (struct obj *, struct monst *));
 STATIC_DCL void FDECL(objlist_sanity, (struct obj *, int, const char *));
@@ -898,11 +899,12 @@ boolean artif;
             switch (otmp->otyp) {
             case TALLOW_CANDLE:
             case WAX_CANDLE:
-                otmp->spe = 1;
-                otmp->age = 20L * /* 400 or 200 */
-                            (long) objects[otmp->otyp].oc_cost;
-                otmp->lamplit = 0;
                 otmp->quan = 1L + (long) (rn2(2) ? rn2(7) : 0);
+                /*FALLTHRU*/
+            case GUIDING_CANDLE:
+                otmp->spe = 1;
+                otmp->age = candle_burn_time(otmp);
+                otmp->lamplit = 0;
                 blessorcurse(otmp, 5);
                 break;
             case BRASS_LANTERN:
@@ -1227,12 +1229,13 @@ int old_range;
 {
     char buf[BUFSZ];
     xchar ox, oy;
-    int new_range = arti_light_radius(obj), delta = new_range - old_range;
+    int new_range = dynamic_light_radius(obj), delta = new_range - old_range;

     /* radius of light emitting artifact varies by curse/bless state
        so will change after blessing or cursing */
-    if (delta) {
+    if (new_range)
         obj_adjust_light_radius(obj, new_range);
+    if (delta) {
         /* simplifying assumptions:  hero is wielding this object;
            artifacts have to be in use to emit light and monsters'
            gear won't change bless or curse state */
@@ -1249,7 +1252,8 @@ int old_range;
                    when changing intensity, using "less brightly" is
                    straightforward for dimming, but we need "brighter"
                    rather than "more brightly" for brightening; ugh */
-                pline("%s %s %s%s.", buf, otense(obj, "shine"),
+                pline("%s %s %s%s.", buf, otense(obj, Is_candle(obj)
+                                                      ? "burn" : "shine"),
                       (abs(delta) > 1) ? "much " : "",
                       (delta > 0) ? "brighter" : "less brightly");
             }
@@ -1272,7 +1276,7 @@ register struct obj *otmp;
     if (otmp->oclass == COIN_CLASS)
         return;
     if (otmp->lamplit)
-        old_light = arti_light_radius(otmp);
+        old_light = dynamic_light_radius(otmp);
     otmp->cursed = 0;
     otmp->blessed = 1;
     if (carried(otmp) && confers_luck(otmp))
@@ -1293,7 +1297,7 @@ register struct obj *otmp;
     int old_light = 0;

     if (otmp->lamplit)
-        old_light = arti_light_radius(otmp);
+        old_light = dynamic_light_radius(otmp);
     otmp->blessed = 0;
     if (carried(otmp) && confers_luck(otmp))
         set_moreluck();
@@ -1313,7 +1317,7 @@ register struct obj *otmp;
     if (otmp->oclass == COIN_CLASS)
         return;
     if (otmp->lamplit)
-        old_light = arti_light_radius(otmp);
+        old_light = dynamic_light_radius(otmp);
     already_cursed = otmp->cursed;
     otmp->blessed = 0;
     otmp->cursed = 1;
@@ -1350,7 +1354,7 @@ register struct obj *otmp;
     int old_light = 0;

     if (otmp->lamplit)
-        old_light = arti_light_radius(otmp);
+        old_light = dynamic_light_radius(otmp);
     otmp->cursed = 0;
     if (carried(otmp) && confers_luck(otmp))
         set_moreluck();
@@ -1768,7 +1772,7 @@ boolean do_buried;
         if (otmp->timed)
             obj_timer_checks(otmp, x, y, 0);
     }
-    if (do_buried) {
+    if (do_buried && levl[x][y].buried) {
         for (otmp = level.buriedobjlist; otmp; otmp = otmp->nobj) {
             if (otmp->ox == x && otmp->oy == y) {
                 if (otmp->timed)
@@ -1955,6 +1959,7 @@ struct obj *obj;
         break;
     case OBJ_BURIED:
         extract_nobj(obj, &level.buriedobjlist);
+        recheck_buried(obj->ox, obj->oy);
         break;
     case OBJ_ONBILL:
         extract_nobj(obj, &billobjs);
@@ -2095,6 +2100,21 @@ struct obj *obj;
     obj->where = OBJ_BURIED;
     obj->nobj = level.buriedobjlist;
     level.buriedobjlist = obj;
+    levl[obj->ox][obj->oy].buried = 1;
+}
+
+STATIC_OVL void
+recheck_buried(x, y)
+int x, y;
+{
+    struct obj *obj;
+    for (obj = level.buriedobjlist; obj; obj = obj->nobj)
+        if (obj->ox == x && obj->oy == y)
+          {
+            levl[x][y].buried = 1;
+            return;
+          }
+    levl[x][y].buried = 0;
 }

 /* Recalculate the weight of this container and all of _its_ containers. */
diff --git c/src/mon.c w/src/mon.c
index 7bb0d0f..a811f5c 100644
--- c/src/mon.c
+++ w/src/mon.c
@@ -1405,7 +1405,7 @@ nexttry: /* eels prefer the water, but if there is no water nearby,
                 && (lavaok || !is_lava(nx, ny))) {
                 int dispx, dispy;
                 boolean monseeu = (mon->mcansee
-                                   && (!Invis || perceives(mdat)));
+                                   && (!Invis || perceives_you(mdat)));
                 boolean checkobj = OBJ_AT(nx, ny);

                 /* Displacement also displaces the Elbereth/scare monster,
@@ -2917,9 +2917,9 @@ int x, y, distance;
     }
 }

-/* NOTE: we must check for mimicry before calling this routine */
+/* also used in detect.c */
 void
-seemimic(mtmp)
+seemimic_noredraw(mtmp)
 register struct monst *mtmp;
 {
     boolean is_blocker_appear = (is_lightblocker_mappear(mtmp));
@@ -2936,7 +2936,14 @@ register struct monst *mtmp;
     if (is_blocker_appear
         && !does_block(mtmp->mx, mtmp->my, &levl[mtmp->mx][mtmp->my]))
         unblock_point(mtmp->mx, mtmp->my);
+}

+/* NOTE: we must check for mimicry before calling this routine */
+void
+seemimic(mtmp)
+register struct monst *mtmp;
+{
+    seemimic_noredraw(mtmp);
     newsym(mtmp->mx, mtmp->my);
 }

diff --git c/src/monmove.c w/src/monmove.c
index 2f7ae6f..e832a23 100644
--- c/src/monmove.c
+++ w/src/monmove.c
@@ -330,7 +330,7 @@ int *inrange, *nearby, *scared;
      * running into you by accident but possibly attacking the spot
      * where it guesses you are.
      */
-    if (!mtmp->mcansee || (Invis && !perceives(mtmp->data))) {
+    if (!mtmp->mcansee || (Invis && !perceives_you(mtmp->data))) {
         seescaryx = mtmp->mux;
         seescaryy = mtmp->muy;
     } else {
@@ -913,7 +913,7 @@ register int after;
                               && (dist2(omx, omy, gx, gy) <= 36));

         if (!mtmp->mcansee
-            || (should_see && Invis && !perceives(ptr) && rn2(11))
+            || (should_see && Invis && !perceives_you(ptr) && rn2(11))
             || is_obj_mappear(&youmonst,STRANGE_OBJECT) || u.uundetected
             || (is_obj_mappear(&youmonst,GOLD_PIECE) && !likes_gold(ptr))
             || (mtmp->mpeaceful && !mtmp->isshk) /* allow shks to follow */
@@ -1550,7 +1550,7 @@ register struct monst *mtmp;
     if (mx == u.ux && my == u.uy)
         goto found_you;

-    notseen = (!mtmp->mcansee || (Invis && !perceives(mtmp->data)));
+    notseen = (!mtmp->mcansee || (Invis && !perceives_you(mtmp->data)));
     /* add cases as required.  eg. Displacement ... */
     if (notseen || Underwater) {
         /* Xorns can smell quantities of valuable metal
diff --git c/src/mthrowu.c w/src/mthrowu.c
index d10d2f1..9e0b1bd 100644
--- c/src/mthrowu.c
+++ w/src/mthrowu.c
@@ -1159,8 +1159,8 @@ int whodidit;   /* 1==hero, 0=other, -1==just check whether it'll pass thru */
             break;
         case TOOL_CLASS:
             hits = (obj_type != SKELETON_KEY && obj_type != LOCK_PICK
-                    && obj_type != CREDIT_CARD && obj_type != TALLOW_CANDLE
-                    && obj_type != WAX_CANDLE && obj_type != LENSES
+                    && obj_type != CREDIT_CARD && !Is_candle(otmp)
+                    && obj_type != LENSES
                     && obj_type != TIN_WHISTLE && obj_type != MAGIC_WHISTLE);
             break;
         case ROCK_CLASS: /* includes boulder */
diff --git c/src/muse.c w/src/muse.c
index ec533c0..c2b0880 100644
--- c/src/muse.c
+++ w/src/muse.c
@@ -727,7 +727,7 @@ struct monst *mtmp;
             pline_The("digging ray is ineffective.");
             return 2;
         }
-        if (!Can_dig_down(&u.uz) && !levl[mtmp->mx][mtmp->my].candig) {
+        if (!Can_dig_hole(mtmp->mx, mtmp->my, &u.uz)) {
             if (canseemon(mtmp))
                 pline_The("%s here is too hard to dig in.",
                           surface(mtmp->mx, mtmp->my));
diff --git c/src/objects.c w/src/objects.c
index fcca3b0..a3f8c99 100644
--- c/src/objects.c
+++ w/src/objects.c
@@ -658,8 +658,9 @@ TOOL("skeleton key",       "key", 0, 0, 0, 0, 80,  3, 10, IRON, HI_METAL),
 TOOL("lock pick",           None, 1, 0, 0, 0, 60,  4, 20, IRON, HI_METAL),
 TOOL("credit card",         None, 1, 0, 0, 0, 15,  1, 10, PLASTIC, CLR_WHITE),
 /* light sources */
-TOOL("tallow candle",   "candle", 0, 1, 0, 0, 20,  2, 10, WAX, CLR_WHITE),
+TOOL("tallow candle",   "candle", 0, 1, 0, 0, 17,  2, 10, WAX, CLR_WHITE),
 TOOL("wax candle",      "candle", 0, 1, 0, 0,  5,  2, 20, WAX, CLR_WHITE),
+TOOL("guiding candle",  "candle", 0, 1, 1, 0,  3,  2, 30, WAX, CLR_WHITE),
 TOOL("brass lantern",       None, 1, 0, 0, 0, 30, 30, 12, COPPER, CLR_YELLOW),
 TOOL("oil lamp",          "lamp", 0, 0, 0, 0, 45, 20, 10, COPPER, CLR_YELLOW),
 TOOL("magic lamp",        "lamp", 0, 0, 1, 0, 15, 20, 50, COPPER, CLR_YELLOW),
diff --git c/src/objnam.c w/src/objnam.c
index 06efd9b..cb0f06d 100644
--- c/src/objnam.c
+++ w/src/objnam.c
@@ -1077,8 +1077,7 @@ unsigned doname_flags;
             break;
         } else if (obj->otyp == OIL_LAMP || obj->otyp == MAGIC_LAMP
                    || obj->otyp == BRASS_LANTERN || Is_candle(obj)) {
-            if (Is_candle(obj)
-                && obj->age < 20L * (long) objects[obj->otyp].oc_cost)
+            if (Is_candle(obj) && obj->age < candle_burn_time(obj))
                 Strcat(prefix, "partly used ");
             if (obj->lamplit)
                 Strcat(bp, " (lit)");
@@ -2668,7 +2667,7 @@ struct o_range {
 STATIC_OVL NEARDATA const struct o_range o_ranges[] = {
     { "bag", TOOL_CLASS, SACK, BAG_OF_TRICKS },
     { "lamp", TOOL_CLASS, OIL_LAMP, MAGIC_LAMP },
-    { "candle", TOOL_CLASS, TALLOW_CANDLE, WAX_CANDLE },
+    { "candle", TOOL_CLASS, TALLOW_CANDLE, GUIDING_CANDLE },
     { "horn", TOOL_CLASS, TOOLED_HORN, HORN_OF_PLENTY },
     { "shield", ARMOR_CLASS, SMALL_SHIELD, SHIELD_OF_REFLECTION },
     { "hat", ARMOR_CLASS, FEDORA, DUNCE_CAP },
@@ -3707,7 +3706,7 @@ struct obj *no_wish;
             typ = FAKE_AMULET_OF_YENDOR;
             break;
         case CANDELABRUM_OF_INVOCATION:
-            typ = rnd_class(TALLOW_CANDLE, WAX_CANDLE);
+            typ = rnd_class(TALLOW_CANDLE, GUIDING_CANDLE);
             break;
         case BELL_OF_OPENING:
             typ = BELL;
@@ -3741,7 +3740,8 @@ struct obj *no_wish;

     /* if player specified a reasonable count, maybe honor it */
     if (cnt > 0 && objects[typ].oc_merge
-        && (wizard || cnt < rnd(6) || (cnt <= 7 && Is_candle(otmp))
+        && (wizard || cnt < rnd(6) || (cnt <= 7 && Is_candle(otmp)
+                                       && !objects[typ].oc_magic)
             || (cnt <= 20 && ((oclass == WEAPON_CLASS && is_ammo(otmp))
                               || typ == ROCK || is_missile(otmp)))))
         otmp->quan = (long) cnt;
diff --git c/src/pager.c w/src/pager.c
index 5ca886d..0b2b07e 100644
--- c/src/pager.c
+++ w/src/pager.c
@@ -167,7 +167,7 @@ struct obj **obj_p;

     *obj_p = (struct obj *) 0;
     /* TODO: check inside containers in case glyph came from detection */
-    if ((otmp = sobj_at(glyphotyp, x, y)) == 0)
+    if ((otmp = sobj_at(glyphotyp, x, y)) == 0 && levl[x][y].buried)
         for (otmp = level.buriedobjlist; otmp; otmp = otmp->nobj)
             if (otmp->ox == x && otmp->oy == y && otmp->otyp == glyphotyp)
                 break;
diff --git c/src/polyself.c w/src/polyself.c
index a8e4342..d8ff152 100644
--- c/src/polyself.c
+++ w/src/polyself.c
@@ -1320,9 +1320,9 @@ dogaze()
             continue;
         if (canseemon(mtmp) && couldsee(mtmp->mx, mtmp->my)) {
             looked++;
-            if (Invis && !perceives(mtmp->data)) {
+            if (Invis && !perceives_you(mtmp->data)) {
                 pline("%s seems not to notice your gaze.", Monnam(mtmp));
-            } else if (mtmp->minvis && !See_invisible) {
+            } else if (minvisible(mtmp) && !See_invisible) {
                 You_cant("see where to gaze at %s.", Monnam(mtmp));
             } else if (M_AP_TYPE(mtmp) == M_AP_FURNITURE
                        || M_AP_TYPE(mtmp) == M_AP_OBJECT) {
diff --git c/src/potion.c w/src/potion.c
index 7d8afd0..5596433 100644
--- c/src/potion.c
+++ w/src/potion.c
@@ -439,7 +439,8 @@ self_invis_message()
     pline("%s %s.",
           Hallucination ? "Far out, man!  You"
                         : "Gee!  All of a sudden, you",
-          See_invisible ? "can see right through yourself"
+          See_invisible || candetect(u.ux, u.uy)
+                        ? "can see right through yourself"
                         : "can't see yourself");
 }

@@ -1680,8 +1681,9 @@ register struct obj *obj;
         if (!Blind && !Invis) {
             kn++;
             pline("For an instant you %s!",
-                  See_invisible ? "could see right through yourself"
-                                : "couldn't see yourself");
+                  See_invisible || candetect(u.ux, u.uy)
+                  ? "could see right through yourself"
+                  : "couldn't see yourself");
         }
         break;
     case POT_PARALYSIS:
diff --git c/src/priest.c w/src/priest.c
index d97886c..646fe5c 100644
--- c/src/priest.c
+++ w/src/priest.c
@@ -213,7 +213,7 @@ register struct monst *priest;
             }
             avoid = FALSE;
         }
-    } else if (Invis)
+    } else if (Invis && !perceives_you(priest->data))
         avoid = FALSE;

     return move_special(priest, FALSE, TRUE, FALSE, avoid, omx, omy, gx, gy);
diff --git c/src/save.c w/src/save.c
index c3ce6d0..efce8d3 100644
--- c/src/save.c
+++ w/src/save.c
@@ -580,7 +580,7 @@ boolean rlecomp;
                     && prm->flags == rgrm->flags && prm->lit == rgrm->lit
                     && prm->waslit == rgrm->waslit
                     && prm->roomno == rgrm->roomno && prm->edge == rgrm->edge
-                    && prm->candig == rgrm->candig) {
+                    && prm->buried == rgrm->buried) {
                     match++;
                     if (match > 254) {
                         match = 254; /* undo this match */
diff --git c/src/shk.c w/src/shk.c
index d5ad782..8ea5562 100644
--- c/src/shk.c
+++ w/src/shk.c
@@ -579,7 +579,7 @@ char *enterstring;
     if (muteshk(shkp) || eshkp->following)
         return; /* no dialog */

-    if (Invis) {
+    if (Invis && !perceives_you(shkp->data)) {
         pline("%s senses your presence.", Shknam(shkp));
         if (!Deaf && !muteshk(shkp))
             verbalize("Invisible customers are not welcome!");
@@ -2177,8 +2177,7 @@ boolean unpaid_only;
             if (saleable(shkp, otmp) && !otmp->unpaid
                 && otmp->oclass != BALL_CLASS
                 && !(otmp->oclass == FOOD_CLASS && otmp->oeaten)
-                && !(Is_candle(otmp)
-                     && otmp->age < 20L * (long) objects[otmp->otyp].oc_cost))
+                && !(Is_candle(otmp) && otmp->age < candle_burn_time(otmp)))
                 price += set_cost(otmp, shkp);
         } else {
             /* no_charge is only set for floor items (including
@@ -3117,8 +3116,7 @@ xchar x, y;
     if ((!saleitem && !(container && cltmp > 0L)) || eshkp->billct == BILLSZ
         || obj->oclass == BALL_CLASS || obj->oclass == CHAIN_CLASS
         || offer == 0L || (obj->oclass == FOOD_CLASS && obj->oeaten)
-        || (Is_candle(obj)
-            && obj->age < 20L * (long) objects[obj->otyp].oc_cost)) {
+        || (Is_candle(obj) && obj->age < candle_burn_time(obj))) {
         pline("%s seems uninterested%s.", Shknam(shkp),
               cgold ? " in the rest" : "");
         if (container)
@@ -3373,8 +3371,7 @@ boolean shk_buying;
             tmp += 10L * (long) obj->spe;
         break;
     case TOOL_CLASS:
-        if (Is_candle(obj)
-            && obj->age < 20L * (long) objects[obj->otyp].oc_cost)
+        if (Is_candle(obj) && obj->age < candle_burn_time(obj))
             tmp /= 2L;
         break;
     }
@@ -3848,7 +3845,7 @@ struct monst *shkp;
         avoid = FALSE;
     } else {
 #define GDIST(x, y) (dist2(x, y, gx, gy))
-        if (Invis || u.usteed) {
+        if (Invis && !perceives_you(shkp->data) || u.usteed) {
             avoid = FALSE;
         } else {
             uondoor = (u.ux == eshkp->shd.x && u.uy == eshkp->shd.y);
@@ -4178,7 +4175,7 @@ boolean cant_mollify;
         return;
     }

-    if (Invis)
+    if (Invis && !perceives_you(shkp->data))
         Your("invisibility does not fool %s!", shkname(shkp));
     Sprintf(qbuf, "%sYou did %ld %s worth of damage!%s  Pay?",
             !animal ? cad(TRUE) : "", cost_of_damage,
@@ -4630,7 +4627,8 @@ register xchar x, y;
         && shkp->mcanmove && !shkp->msleeping
         && (ESHK(shkp)->debit || ESHK(shkp)->billct || ESHK(shkp)->robbed)) {
         pline("%s%s blocks your way!", Shknam(shkp),
-              Invis ? " senses your motion and" : "");
+              Invis && !perceives_you(shkp->data) ? " senses your motion and"
+                                                  : "");
         return TRUE;
     }
     return FALSE;
@@ -4664,10 +4662,11 @@ register xchar x, y;

     if (shkp->mx == sx && shkp->my == sy && shkp->mcanmove && !shkp->msleeping
         && (x == sx - 1 || x == sx + 1 || y == sy - 1 || y == sy + 1)
-        && (Invis || carrying(PICK_AXE) || carrying(DWARVISH_MATTOCK)
-            || u.usteed)) {
+        && (Invis && !perceives_you(shkp->data) || carrying(PICK_AXE)
+            || carrying(DWARVISH_MATTOCK) || u.usteed)) {
         pline("%s%s blocks your way!", Shknam(shkp),
-              Invis ? " senses your motion and" : "");
+              Invis && !perceives_you(shkp->data) ? " senses your motion and"
+                                                  : "");
         return TRUE;
     }
     return FALSE;
diff --git c/src/shknam.c w/src/shknam.c
index a36b67e..cb54cc7 100644
--- c/src/shknam.c
+++ w/src/shknam.c
@@ -330,8 +330,9 @@ const struct shclass shtypes[] = {
       TOOL_CLASS,
       0,
       D_SHOP,
-      { { 30, -WAX_CANDLE },
-        { 48, -TALLOW_CANDLE },
+      { { 25, -WAX_CANDLE },
+        { 38, -TALLOW_CANDLE },
+        { 15, -GUIDING_CANDLE },
         { 5, -BRASS_LANTERN },
         { 9, -OIL_LAMP },
         { 3, -MAGIC_LAMP },
diff --git c/src/timeout.c w/src/timeout.c
index a4408de..c02319f 100644
--- c/src/timeout.c
+++ w/src/timeout.c
@@ -594,7 +594,7 @@ nh_timeout()
             case INVIS:
                 newsym(u.ux, u.uy);
                 if (!Invis && !BInvis && !Blind) {
-                    You(!See_invisible
+                    You(!See_invisible && !candetect(u.ux, u.uy)
                             ? "are no longer invisible."
                             : "can no longer see through yourself.");
                     stop_occupation();
@@ -1249,6 +1249,7 @@ long timeout;
     case CANDELABRUM_OF_INVOCATION:
     case TALLOW_CANDLE:
     case WAX_CANDLE:
+    case GUIDING_CANDLE:
         switch (obj->age) {
         case 75:
             if (canseeit)
@@ -1411,6 +1412,7 @@ boolean already_lit;
     int radius = 3;
     long turns = 0;
     boolean do_timer = TRUE;
+    boolean detect = FALSE;

     if (obj->age == 0 && obj->otyp != MAGIC_LAMP && !artifact_light(obj))
         return;
@@ -1443,6 +1445,10 @@ boolean already_lit;
             turns = obj->age;
         break;

+    case GUIDING_CANDLE:
+        if (!obj->cursed)
+            detect = TRUE;
+        /* fall through */
     case CANDELABRUM_OF_INVOCATION:
     case TALLOW_CANDLE:
     case WAX_CANDLE:
@@ -1461,7 +1467,7 @@ boolean already_lit;
         if (artifact_light(obj)) {
             obj->lamplit = 1;
             do_timer = FALSE;
-            radius = arti_light_radius(obj);
+            radius = dynamic_light_radius(obj);
         } else {
             impossible("begin burn: unexpected %s", xname(obj));
             turns = obj->age;
@@ -1487,7 +1493,9 @@ boolean already_lit;
         xchar x, y;

         if (get_obj_location(obj, &x, &y, CONTAINED_TOO | BURIED_TOO))
-            new_light_source(x, y, radius, LS_OBJECT, obj_to_any(obj));
+            new_light_source(x, y, radius,
+                             detect ? LS_OBJECT | LS_DETECT : LS_OBJECT,
+                             obj_to_any(obj));
         else
             impossible("begin_burn: can't get obj position");
     }
diff --git c/src/trap.c w/src/trap.c
index 02d1030..7a06ff0 100644
--- c/src/trap.c
+++ w/src/trap.c
@@ -487,7 +487,7 @@ boolean td; /* td == TRUE : trap door or hole */
     if (Sokoban && Can_fall_thru(&u.uz))
         ; /* KMH -- You can't escape the Sokoban level traps */
     else if (Levitation || u.ustuck
-             || (!Can_fall_thru(&u.uz) && !levl[u.ux][u.uy].candig) || Flying
+             || !Can_fall_thru(&u.uz) || Flying
              || is_clinger(youmonst.data)
              || (Inhell && !u.uevent.invoked && newlevel == bottom)) {
         dont_fall = "don't fall in.";
diff --git c/src/uhitm.c w/src/uhitm.c
index f478d02..fdbc616 100644
--- c/src/uhitm.c
+++ w/src/uhitm.c
@@ -3008,7 +3008,7 @@ struct monst *mtmp;

         /* cloned Wiz starts out mimicking some other monster and
            might make himself invisible before being revealed */
-        if (mtmp->minvis && !See_invisible)
+        if (minvisible(mtmp) && !See_invisible)
             what = generic;
         else
             what = a_monnam(mtmp);
diff --git c/src/vision.c w/src/vision.c
index b8ce2e5..2b95930 100644
--- c/src/vision.c
+++ w/src/vision.c
@@ -513,6 +513,7 @@ int control;
     int dx, dy;        /* one step from a lit door or lit wall (see below) */
     register int col;  /* inner loop counter */
     register struct rm *lev; /* pointer to current pos */
+    struct obj *otmp;  /* for iterating through inventory */
     struct rm *flev; /* pointer to position in "front" of current pos */
     extern unsigned char seenv_matrix[3][3]; /* from display.c */
     static unsigned char colbump[COLNO + 1]; /* cols to bump sv */
@@ -570,6 +571,17 @@ int control;
                     newsym(col, row);
         }

+        /* Check if the invisible hero can be seen because of their guiding
+         * candle (normally would be checked below).  We don't check for
+         * nearby candles (on the ground or held by monsters) because that's
+         * too much effort for too rare an occurence.
+         */
+        for (otmp = invent; otmp; otmp = otmp->nobj)
+            if (otmp->otyp == GUIDING_CANDLE && otmp->lamplit) {
+                viz_array[u.uy][u.ux] |= TEMP_DETECT;
+                break;
+            }
+
         /* skip the normal update loop */
         goto skip;
     } else if (Is_rogue_level(&u.uz)) {
@@ -737,8 +749,10 @@ int control;
                 lev->seenv |=
                     new_angle(lev, sv, row, col); /* update seen angle */

-                /* Update pos if previously not in sight or new angle. */
-                if (!(old_row[col] & IN_SIGHT) || oldseenv != lev->seenv)
+                /* Update pos if previously not in sight or new angle
+                 * or when entering/leaving the radius of guiding candle. */
+                if (!(old_row[col] & IN_SIGHT) || oldseenv != lev->seenv
+                    || (old_row[col] ^ next_row[col]) & TEMP_DETECT)
                     newsym(col, row);

             } else if ((next_row[col] & COULD_SEE)
@@ -766,9 +780,11 @@ int control;
                         lev->seenv |= new_angle(lev, sv, row, col);

                         /* Update pos if previously not in sight or new
-                         * angle.*/
+                         * angle or when entering/leaving the radius of
+                         * guiding candle. */
                         if (!(old_row[col] & IN_SIGHT)
-                            || oldseenv != lev->seenv)
+                            || oldseenv != lev->seenv
+                            || (old_row[col] ^ next_row[col]) & TEMP_DETECT)
                             newsym(col, row);
                     } else
                         goto not_in_sight; /* we don't see it */
@@ -779,8 +795,10 @@ int control;
                     oldseenv = lev->seenv;
                     lev->seenv |= new_angle(lev, sv, row, col);

-                    /* Update pos if previously not in sight or new angle. */
-                    if (!(old_row[col] & IN_SIGHT) || oldseenv != lev->seenv)
+                    /* Update pos if previously not in sight or new angle or
+                     * when entering/leaving the radius of guiding candle. */
+                    if (!(old_row[col] & IN_SIGHT) || oldseenv != lev->seenv
+                        || (old_row[col] ^ next_row[col]) & TEMP_DETECT)
                         newsym(col, row);
                 }
             } else if ((next_row[col] & COULD_SEE) && lev->waslit) {
@@ -2806,7 +2824,7 @@ struct monst *mon;
     if (useemon && mon->minvis)
         how_seen |= MONSEEN_SEEINVIS;
     /* infravision */
-    if ((!mon->minvis || See_invisible) && see_with_infrared(mon))
+    if ((!minvisible(mon) || See_invisible) && see_with_infrared(mon))
         how_seen |= MONSEEN_INFRAVIS;
     /* telepathy */
     if (tp_sensemon(mon))
diff --git c/src/worn.c w/src/worn.c
index 1a966b7..05328b3 100644
--- c/src/worn.c
+++ w/src/worn.c
@@ -522,7 +522,7 @@ boolean racialexception;
         return; /* probably putting previous item on */

     /* Get a copy of monster's name before altering its visibility */
-    Strcpy(nambuf, See_invisible ? Monnam(mon) : mon_nam(mon));
+    Strcpy(nambuf, mon_nam(mon));

     old = which_armor(mon, flag);
     if (old && old->cursed)
@@ -640,7 +640,7 @@ outer_break:
     update_mon_intrinsics(mon, best, TRUE, creation);
     /* if couldn't see it but now can, or vice versa, */
     if (!creation && (unseen ^ !canseemon(mon))) {
-        if (mon->minvis && !See_invisible) {
+        if (minvisible(mon) && !See_invisible) {
             pline("Suddenly you cannot see %s.", nambuf);
             makeknown(best->otyp);
         } /* else if (!mon->minvis) pline("%s suddenly appears!",
diff --git c/src/zap.c w/src/zap.c
index a9350eb..ec6526a 100644
--- c/src/zap.c
+++ w/src/zap.c
@@ -3353,7 +3353,7 @@ struct obj **pobj; /* object tossed/used, set to NULL
                    prepared for multiple hits so just get first one
                    that's either visible or could see its invisible
                    self.  [No tmp_at() cleanup is needed here.] */
-                if (!mtmp->minvis || perceives(mtmp->data))
+                if (!minvisible(mtmp) || perceives(mtmp->data))
                     return mtmp;
             } else if (weapon != ZAPPED_WAND) {