Double chu Fire Fences room

O = works
x = doesn't work
f = forward slide
  = I haven't tested

--- link touching the smaller block, aligned ---
    press Z+R on                    1st  2nd  3rd  4th  5th  6th  7th      hit frame

Roll 4 frame after 2nd chu press :        x    x
Roll 5 frame after 2nd chu press :        O    O    f
Roll 6 frame after 2nd chu press :        O    O    O    f
Roll 7 frame after 2nd chu press :        O    O    f
Roll 7 frame after 2nd chu press :        dmg