H. G. Muller wrote on Wed, Jul 9, 2008 08:09 AM UTC:
'On 2008-07-06 H. G. Muller concluded that King and Bison can force checkmate on boards as large as 12x12. '
That was actually even 14x14. King + Bison vs Kings is absolutely won on 14x14 and smaller, with white to move. (i.e. not a single draw position.) The Bison cannot be trapped in a corner; its large stride simply makes it leap out of trouble. In addition there are no corner stalemates (such as in KNK:
k N . . . . ), because a Bison can alway check the square
. . . . . next to it in 1 move.
K . . . .
. . . .
.
The longest mates (against perfect defense) are:
BOARD MOVES (K,Bi,k)
16x16: 76 (a4,b7,b1) (but 90% of all wtm positions are draw)
14x14: 82 (a1,n14,c3) (100% won)
12x12: 55 (a1,L12,c3) '
10x10: 40 (a1,j10,c3) '
8x8: 27 (a2,b2,b4) '