Gomoku Β· Complete guide
Gomoku: how to play five in a row, and how to win
Five stones in a line on a Go board. Simple enough for a child, and so favourable to the first player that two separate rule systems exist to fix it.
Gomoku is five in a row on a Go board: place a stone, make an unbroken line of five, win. It takes ten seconds to explain and it is played everywhere Go boards exist.
It is also a game with a famous flaw. The first player wins β that is not an opinion but a proved result, demonstrated for freestyle Gomoku in 1993 and for the restricted Renju version in 2001. Threats build faster than they can be blocked, so the player who moves first gets to a double threat first.
Everything interesting about the game comes from managing that. Renju handicaps Black by forbidding double threes, double fours and overlines. Swap2 balances the game differently, by letting one player set up an opening position and the other choose which colour to take β so the setter has to make it fair. Casual play usually just accepts that going first is an advantage.
Underneath the rule arguments is a genuinely sharp tactical game. Fours force a reply, open threes force a reply, and the entire art is chaining forced moves until two threats intersect.
How to play
Five in a row on a 15Γ15 board, plus the reason the game has three rule sets: the first player wins unless something stops them. Freestyle, standard, Renju's forbidden moves and Swap2 explained.
Where it comes from
A game that came free with every Go board, a Japanese reform in 1899 to fix its broken balance, and two computer proofs confirming what players always suspected: the first player wins.
- Gomoku arose wherever Go boards were used β China, Japan and Korea all have their own name for it.
- Ruikou Kuroiwa proposed Renju in 1899 with restrictions on Black to fix the game's imbalance.
- Victor Allis proved in 1993 that freestyle Gomoku is a first-player win.
- Renju was also proved a first-player win in 2001, which is why balancing openings are now used.
How to win
Blocking open threes and building double threats for beginners, VCF forcing sequences for intermediates, and threat-space search, opening theory and Renju technique for advanced players.
- Fours and open threes are forcing β whoever keeps making them controls the game.
- Every win comes from a double threat: a four-three, a double three or a double four.
- Block open threes immediately, and prefer the block that also threatens something of yours.
- Count a forcing sequence (VCF) to the end before you start it; spent fours are dead shapes.
Gomoku strategy: threats, forcing moves and double threats β
Common questions
Does the first player always win at Gomoku?
With perfect play, yes β proved for freestyle in 1993 and for Renju in 2001. In practice, at human level, the advantage is real but not decisive unless both players are strong.
What is the difference between Gomoku and Renju?
Renju is the competitive Japanese version, which bans Black from double threes, double fours and overlines to offset the first-player advantage.
Does six in a row count?
In freestyle, yes. In standard Gomoku and Renju an overline does not win for Black β and in Renju it actually loses.
What is the best first move?
The centre. It has the most lines running through it, and all opening theory in both Gomoku and Renju begins there.
How do I stop losing to double threats?
Block every open three immediately, answer every four, and look for blocks that also create a threat of your own so you take back the initiative.
Guides
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