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Gomoku looks innocent - drop a stone, line up five, done - but on Classic Play Games' 9x9, 13x13, or 15x15 board it quickly becomes a duel of threats and counter-threats. Black moves first, usually onto the center point, and from there every stone either builds toward your own five or smothers your opponent's. There are no captures, no dice, and no territory to count: the win is purely a race to forge an unbroken line of five before the other side does, while reading two or three moves ahead.
How to Play Gomoku
Gomoku is played here on a 9x9, 13x13, or 15x15 grid (Auto picks one that fits your screen) by two players, Black and White. Black always moves first. On your turn you place one stone on any empty intersection; once placed, stones never move and are never captured. Play alternates until someone wins or the board fills. This version is free-style Gomoku - no opening restrictions, no swap rule, and no forbidden moves - so Black keeps a genuine first-move advantage. When you play against the computer you choose Black, White, or Random before the game; pick Black to get that first move.
You win the instant you form an unbroken line of five of your own stones horizontally, vertically, or diagonally. A line of six or more (an overline) also counts as a win here - it is not forbidden - so a run of five anywhere inside a longer chain still ends the game in your favor. If every intersection is filled and neither side has made five, the game is scored as a draw, though draws are rare.
Against the computer you pick one of three levels before starting. All three use the same evaluation and think for a limited time on each move. Easy thinks briefly and picks at random among its four best moves, so it sometimes leaves open threes and forks standing. Medium thinks longer and picks between its two best. Hard thinks longest, first looks for a forced win by a sequence of fours, and always plays the best move it finds. One thing every level always does first, before any search: it takes an immediate winning move if it has one, and otherwise blocks a spot where you would otherwise complete five on your next turn. The catch is that this guard only patches a single five-completion - it cannot stop an open four, which threatens five at both ends, so an open four wins unless the computer has a five of its own to complete first. Local two-player mode shares one device and alternates turns.
Playing Against the Computer
The computer's evaluation scores an open four as a won position and an open three left unanswered at half that value, so a searching AI will drop almost anything to stop your three before it becomes an open four. Its opening is hardwired at every level: as Black it opens on the center (H8 on the 15x15 board), and it answers a center stone with the adjacent diagonal up and to the left (G7 on 15x15), which is not a sign of deep thinking. After that it searches, with a small center bonus in its scoring, so stones drifting toward the edges are worth less to it. The deeper Medium and especially Hard punish a missed open three of theirs immediately.
To beat it, remember that its mandatory guard only blocks a single immediate five-completion: a clean open four (_XXXX_) wins even against Hard, as long as the computer has no five of its own to complete first. When it kills your open threes in time, build a double threat it can only half-answer.
Frequently Asked Questions
Does six in a row (an overline) count as a win in this Gomoku?
Yes. This is free-style Gomoku, so any unbroken line of five or more of your stones wins - six, seven, or longer all count. Some tournament rule sets forbid overlines for Black, but that restriction is not used here, so you never have to worry about accidentally overshooting five.
Is there a swap rule or any restriction on Black's opening?
No. There is no swap, no pie rule, and no forbidden first moves. Black opens on any intersection and play proceeds freely. When you play the computer you choose Black, White, or Random; as Black you get the first-move advantage - most players open on the center point (H8 on the 15x15 board), and the AI then replies on the adjacent diagonal (G7).
Can the AI ever let my five-in-a-row through?
Every level always takes an immediate win if it has one, and otherwise always blocks a single spot where you would complete five next turn - so a plain closed four (one open end) gets stopped every time. But that guard only patches one completion point, so an open four, with five available at both ends, beats every level including Hard, unless the computer can complete a five of its own first. The reliable ways to win are an open four or a double threat the AI can only half-answer.
What actually changes between Easy, Medium, and Hard?
Thinking time and how each level chooses. All three use the same evaluation. Easy thinks briefly and picks at random among its four best moves, so it sometimes leaves open threes and forks standing. Medium thinks longer and picks between its two best. Hard thinks longest, first looks for a forced win by a sequence of fours, and always plays the best move it finds, so it reliably kills your open threes before they become open fours. All three still take immediate wins, and otherwise block immediate fives, regardless of level.
Why does the computer always answer my center stone in the same spot?
Because that reply is hardcoded. If you play Black and open on the center (H8 on the 15x15 board), the AI plays the adjacent diagonal up and to the left (G7; F6 on 13x13, D4 on 9x9) every time, at any difficulty, before it does any searching at all. After that fixed second move it switches to real evaluation, which adds a center bonus so middle stones are scored higher - which is why strong play, human or AI, gravitates toward the center.