Gomoku rules — how to play

The goal

Be the first to get five of your stones in an unbroken line: horizontal, vertical or diagonal.

The board

The board starts small and grows as stones reach the edge — there is no fixed border. Drag the board, or swipe on a phone, to move around. Tap or click an empty intersection to place a stone.

Board size and the endless grid

Traditional gomoku is usually played on a 15×15 grid, and renju uses the same size. Caro Classic uses an endless board instead: it begins small and adds rows and columns when stones reach the edge. That means there is no fixed border to run into, and long games have room to continue.

Turns

Black moves first and you always play Black. In “vs AI” the computer plays White. In “2 players” two people share the device and take turns.

Caro, gomoku and renju

Caro is the Vietnamese name for gomoku, also called five in a row or gobang. Renju is the competitive variant: it uses opening rules and forbidden moves to reduce Black's first-player advantage. Caro Classic plays free-style gomoku — no forbidden moves, no captures, and the first player to line up five wins.

Controls

• New game: start over; scores are kept for the session.
• Undo: take back one stone. Against the AI it also takes back the computer's reply, so you get the same position to rethink.
• Sound: mute or unmute the bamboo flute and the wooden stone clicks.
• Share (S): copy a replay link for the current game.
• Rotate and full screen on desktop.

No extra rules

There are no captures and no forbidden moves. This is free-style gomoku, not renju. Five in a row wins immediately.

Tips for your first game

• Start near the centre; stones there have more room to grow in every direction.
• Watch both ends of every line, not only your own stones.
• If the AI blocks you, look for a second line instead of repeating the same attack.
• Use Undo against the AI to try a different move from the same position.

Common beginner mistakes

• Watching only one line and ignoring the rest of the board.
• Blocking a three but missing the opponent's open four.
• Starting far from existing stones, where a new line has less room to grow.

Frequently asked questions