Keysanity key usage/requirements guide

What can I do with my small keys in keysanity mode?

First, here's a table of key counts for each dungeon.
"keys": how many small keys are available to pick up
"go mode": minimum keys needed to go mode the dungeon optimally
"logic": minimum keys the logic expects you to need to complete the dungeon
"clear": minimum keys needed to full clear the dungeon optimally
+ refers to big key
parentheses refer to items that must be possessed to achieve the specified key count (B is bow, H is hammer, S is cane of somaria, HS is hookshot) -- if you don't have these items, you need an additional small key

dungeon  | keys     | go mode  | logic    | clear
EP       | 0        | 0+       | 0+       | 0+
DP       | 1        | 0+       | 1+       | 1+
ToH      | 1        | 0+       | 0+       | 1+
PoD      | 6        | 1+       | 6+       | 5+ (B,H)*
SP       | 1        | 1        | 1        | 1+
SW       | 3        | 0        | 3        | 0+
TT       | 1        | 0+       | 1+       | 1+
IP       | 2        | 0        | 1+ (S)   | 0+ (HS)**
MM       | 3        | 0+       | 0+       | 0+
TR       | 4        | 3+       | 4+       | 4+
GT       | 4        | 0+       | 4+       | 2+

* hammer jump can save another key in PoD
** a bomb jump in the hookshot room can eliminate the need for hookshot in IP

Hyrule Castle / Sewers:
- 0 Keys: can reach all locations.

Eastern Palace:
- 0 Keys: can reach all locations.
- Big Key: required for 2 locations (big chest, boss).

Desert Palace:
- 0 Keys: can reach the torch, map chest (far north), and big chest.
- 1 Key: can reach the two chests on the right side. (You can steal a key from the back to do this, but then you need the outside key to finish the dungeon.)
- Big Key: required for 2 locations (big chest, boss).

Tower of Hera:
- 0 Keys: can reach every location except the basement.
- 1 Key: can reach the basement.
- Big Key: required for 3 locations (compass, big chest, boss).

Castle Tower:
- 0 Keys: can reach the first chest.
- 1 Key: can reach the second chest.
- 2 Keys: can finish the dungeon.

Palace of Darkness:
- KEY SKIP: having both bow and hammer lets you skip the front door, saving a key. If so, add one to your effective key count when reading below.
- KEY SKIP: performing the hammer jump lets you skip the dark maze door, saving a key. If so, add one to your effective key count when reading below.
- 0 Keys: can reach the first chest and, if bow, the two chests on the right.
- 1 Key: can reach EITHER the bridge chest and the stalfos basement chest OR, if bow and hammer, finish the dungeon.
- 2 Keys: can reach EITHER the big key chest OR open the back door, reaching the compass chest and dark basement chests OR, if bow and hammer, finish the dungeon.
- 3 Keys: can open the back door and also reach EITHER the big key chest OR the harmless hellway chest OR the dark maze chests OR, if bow and hammer, finish the dungeon.
- 4 Keys: can open the back door and reach two of the options given in "3 Keys".
- 5 Keys: can open the back door and reach three of the options given in "3 Keys".
- 6 Keys: can fully clear the dungeon.
- Big Key: required for 2 locations (big chest, boss).

Swamp Palace:
- 0 Keys: can reach the entrance chest. (NOTE: in v27 this either contains the swamp small key or junk! It cannot have a progression item. This is fixed in v28.)
- 1 Key: can reach all locations.
- Big Key: required for 1 location (big chest).

Skull Woods:
- 0 Keys: can reach all locations.
- Big Key: required for 1 location (big chest).

Thieves' Town:
- 0 Keys: can reach all locations except the big chest.
- 1 Keys: can reach the big chest.
- Big Key: required for 4 locations (upstairs, maiden, big chest, boss).

Ice Palace:
- 0 Keys: can reach all locations except the boss, unless you perform Ice Palace bomb jump (IPBJ).
- 1 Key: can reach all locations if you have cane OR perform IPBJ.
- 2 Keys: can reach all locations.
- Big Key: required for 2 locations (big chest, boss) OR 1 location if you perform IPBJ (big chest).

Misery Mire:
- 0 Keys: can reach all locations.
- Big Key: required for 2 locations (big chest, boss).

Turtle Rock:
- 0 Keys: can reach the three chests accessible from the first main room.
- 1 Key: can reach the chain chomp chest.
- 2 Keys: can reach EITHER the big key chest OR crystaroller room and laser bridge.
- 3 Keys: can reach laser bridge, plus EITHER the big key chest OR the boss.
- 4 Keys: can reach all locations.
- Big Key: required for 6 locations (crystaroller room, laser bridge, boss).

Ganon's Tower:
- 0 Keys: can reach all of left side before randomizer room, the first two right side chests, and tile room.
- 1 Key: can reach Bob's chest, ice Armos and EITHER randomizer room OR the compass room on right side.
- 2 Keys: can reach all locations.
- Big Key: required for 4 locations (mini helmas, before Moldorm 2, validation).