Comparison · 5 min

Caro, Gomoku and Tic-Tac-Toe: What's the Difference?

People often mix up caro, gomoku and tic-tac-toe because they all involve lining up pieces. The biggest differences are the size of the board and how many pieces you need to win.

Caro in Vietnam

Caro is the common Vietnamese name for the five-in-a-row game. The board is usually 15×15 or larger, but local rules can vary: some groups count a line of five as a win even when both ends are blocked, while others do not. Caro Classic uses a simple rule set: five consecutive stones win, with no capture and no forbidden moves. That makes it easy to learn while still leaving plenty of room for strategy.

Gomoku

Gomoku is the Japanese name for the five-in-a-row game. The standard board is 15×15, Black moves first, and there are no forbidden moves. Of all the versions in this comparison, free-style gomoku is the closest to casual caro: the same basic goal, the same simple turn structure and the same focus on building connected shapes.

Renju

Renju is the competitive variant of gomoku. Black is forbidden from making a double three, a double four or a line of more than five stones, and committing one of those moves loses the game. The restrictions exist to reduce the first player's advantage, and they are used in international competition. Renju therefore rewards precise calculation as well as shape-building.

Tic-tac-toe

Tic-tac-toe is played on a 3×3 board and only requires three in a row. With optimal play from both sides, the game always ends in a draw. That small board and short winning line make it a very different experience from caro or gomoku: there is no room for a long opening, and almost every position can be worked out by hand.

Quick comparison

Caro: five in a row, large board, varied local rules.
Gomoku: five in a row, 15×15 board, no forbidden moves.
Renju: five in a row, 15×15 board, forbidden moves for Black.
Tic-tac-toe: three in a row, 3×3 board, usually a draw.

Which rules does Caro Classic use?

Caro Classic plays free-style gomoku on an expanded board: no forbidden moves, no capturing, and the first player to connect five stones wins. The expanded board means a long game is not cut short by a fixed edge, and it gives both players more room to build multiple threats. If you already play caro casually, the transition should feel familiar.