For a game of k in a row on an n x n board, for what values of k and n is there a win?
competition/games/go-moku Added material
Problem
For a game of k in a row on an n x n board, for what values of k and n is there a win? Is (the largest such) k eventually constant or does it increase with n?
Show solution
Berlekamp, Conway, and Guy's _Winning_Ways_ reports proof that the
maximum k is between 4 and 7 inclusive, and it appears to be 5 or 6.
They report:
. 4-in-a-row is a draw on a 5x5 board (C. Y. Lee), but not on a 4x30
board (C. Lustenberger).
. N-in-a-row is shown to be a draw on a NxN board for N>4, using a
general pairing technique devised by A. W. Hales and R. I. Jewett.
. 9-in-a-row is a draw even on an infinite board, a 1954 result of H. O.
Pollak and C. E. Shannon.
. More recently, the pseudonymous group T. G. L. Zetters showed that
8-in-a-row is a draw on an infinite board, and have made some
progress on showing infinite 7-in-a-row to be a draw.
Go-moku is 5-in-a-row played on a 19x19 go board. It is a win for the
first player, even in the case where 6-in-a-row doesn't win, which was
proved by:
L.V. Allis, H.J. van den Herik, and M.P.H.Huntjens, "Go-Moku solved by
new search techniques", pp.1-9 in "Proc. AAAI Fall Symposium on Games:
Planning and Learning," AAAI Press Tech. Report FS93-02, 1993, Menlo
Park, CA
References:
http://www.cs.vu.nl/~victor/thesis.html
Additional material
In "Games of No Chance," by MSRI [Editor: "MRSI" in the original] Publications, Volume 29, 1996, the section "Solving Nine Men's Morris," by Ralph Gasser, states that Go-Moku has been solved. He gives the reference L.V. Allis, H.J. van den Herik, and M.P.H.Huntjens, "Go-Moku solved by new search techniques", pp.1-9 in "Proc. AAAI Fall Symposium on Games: Planning and Learning," AAAI Press Tech. Report FS93-02. Menlo Park, CA which is not in my library, so I don't know the details. However, another article in the book states "In an earlier edition of this paper, I asked if Go-Moku . . . is a win for the first player. An affirmative answer for the unrestricted version and for the version where 6-in-a-row doesn't count as a win was given by Allis, van den Herik and Huntjens [1993]" -- Monwhea Jeng <momo@physics.ucsb.edu>