Small boards

Playing Hex on boards of size smaller than 10 × 10 is not very interesting, since many players will be able to play almost perfectly. However it may still be interesting for theoretical studies, and for making problems.

The boards of size up to five can be solved by hand. Hex on 6 × 6 has been solved by Queenbee. The board sizes 7 to 9 have been solved with computer programs, too.

Here are the winning first moves on the small boards. Red is vertical and plays first. The cells shaded red are winning moves for red, while those shaded blue are losing.

Winner depending on the first move

The following boards can help you decide where you should swap when playing on small boards, and it might give you ideas of patterns for bigger boards.

Size 7

Size 7 was first solved by Ryan Hayward using domination. The proof tree can be found at http://www.cs.ualberta.ca/~hayward/hex7trees/

Size 8

The outcomes for size 8 were computer generated by Javerberg. The solution was independently computer generated by Hayward et al. and appeared in IJCAI09.

Size 9

The outcomes for size 9 by Jakub Pawlewicz and Ryan Hayward.

Size 10

The 10 × 10 board has not been solved, though one can make educated guesses from the swap maps of strong bots. In particular, according to the swap map of KataHex, the outcomes for size 10 are as follows:

Only the cells marked "*" have been proven (by humans) to be winning or losing; the other cells are not completely certain. KataHex assigns a winning probability of at least 94.4% (in self-play) for every cell it believes is winning, and at most 2.6% for every cell it believes is losing. Note this does not mean that the bot is at least 94.4% sure of each cell's outcome, only that it thinks it has a 94.4% win rate with the winning side in self-play. However, the probabilities being so close to 0 and 1 suggest the bot is quite confident in its assessment.

Reference

• This article by Ryan Hayward et al. is a reference for 7x7.
• This Little Golem's forum thread is a reference for size 8x8.
• This article by Jakub Pawlewicz and Ryan Hayward is a reference for size 9x9.

See also

• Board size
• Yang, Liao, and Pawlak designed a decomposition method to find a winning strategy for Hex on small boards.
• For corresponding information on the game of Y, please visit Where to swap (y).