Freestyle
The best-known gomoku rule. Either color wins by connecting five or more in any direction — no forbidden moves, and an overline of six still counts.
Cờ caro — a five sealed at both ends does not win
The most popular way to play gomoku in Vietnam. Complete five and the game still continues if the opponent has capped both ends of the line.
The winning condition — an open five
Connect exactly five stones in a row — horizontally, vertically, or diagonally. Six or more never counts.
If the finished five has an opponent stone at both ends, it does not win. That is the signature chặn hai đầu rule.
A five sealed at only one end still wins, and so does a five touching the board edge — the edge is an open end; only stones block.
Why it plays differently — a door opens for the defender
Under ordinary rules an open four is nearly fatal. In cờ caro, completing a five between two enemy stones makes a dead five — no win, and a wasted turn.
That also works the other way: seal both ends of the opponent's line and their five is neutralized.
So attacks must secure the ends as well — win with a five the opponent cannot seal in time, or force the issue with double threats.
How it compares
Freestyle counts six or more, and exact five does not care about the ends at all. Cờ caro adds the both-ends condition on top of exactly five.
There are no forbidden moves like Renju's. Both sides play the same rule, and the sealing condition applies to everyone.
This is the standard way the game is played across Vietnam, from schoolyard paper grids to online rooms.
Common questions
Does six in a row win?
No. Cờ caro counts exactly five. A line of six or more is never a win.
What if only one end is blocked?
It still wins. Only a five with opponent stones at both ends fails — a single sealed end is fine.
Does a five touching the board edge win?
Yes. The edge is an open end — only opponent stones seal. A five reaching the edge wins unless its other end is capped too.
See the other rules
Exact five
Exactly five in a row wins; a line of six or more does not. A simple compromise that weakens Black's overline attacks without forbidden moves.
Renju
The official RIF rule. Forbidden moves — double-three, double-four and overline — apply to Black alone to erase the first-move advantage. White is unrestricted.
Renju · official opening
Renju forbidden moves plus the RIF opening: first move on the center, second inside 3×3, third inside 5×5, then White may swap colors and Black offers two fifth moves.
Gomoku · Swap2
The world-championship opening. One side places black-white-black, and the opponent either picks a color or adds two stones and hands the choice back. Wins need exactly five.