The longest 2x2 game possible seems to be 46 [1]. I can't find the source for the number given by tromp either. But considering that log_2(386,356,909,593) = ~

The longest 2x2 game possible seems to be 46 [1]. I can't find the source for the number given by tromp either. But considering that log_2(386,356,909,593) = ~ 38 and log_3(386,356,909,593) = ~24. If the board can have a branching factor of 2.5 on average for a game length of 30 moves, the number seems reasonable. There are 81 possible states (counting illegal states), and seems to be about 50 legal states. And I'd imagine any given state on a 2x2 board would easily have more than 2 possible moves :-). [1]: http://senseis.xmp.net/?LongestPossibleGame#toc6 http://senseis.xmp.net/?LongestPossibleGame#toc6