3x3 Minimax Draw • 15x15 Grid • 5-in-a-Row • 4-3 Double Threat Forks
Tic-Tac-Toe requires 3-in-a-row on a 3x3 grid. Gomoku (五子棋) requires 5-in-a-row horizontally, vertically, or diagonally on a 15x15 Go grid!
In both games, Player 1 (X or Black stone) holds initiative. In Gomoku, Black moves first on the center star point (K8).
Connecting 5 continuous stones wins Gomoku immediately!
Click scenarios below to learn the optimal corner-opening defense!
Taking the center square gives Player 1 the maximum number of potential winning lines (4 lines)!
YES! Under Minimax algorithm evaluation, if both players play perfectly, Tic-Tac-Toe is 100% guaranteed to result in a Draw. Player 1 can force a draw or win if Player 2 makes a mistake.
An **Open-Three (活三)** is a line of 3 stones with both ends open that can become an Open-Four on the next turn. An **Open-Four (活四)** is a line of 4 unblocked stones with open ends; it guarantees a win on the very next turn because the opponent can only block one end!
A **4-3 Fork** occurs when a single stone placement simultaneously creates an Open-Four (活四) AND an Open-Three (活三). The opponent is forced to block the Open-Four, leaving the Open-Three to convert into a winning 5-in-a-row!
In professional Renju rules, Black is forbidden from forming Double-Three (3-3), Double-Four (4-4), or Overlines (6+ stones in a row). White has no restrictions!
Creating an Open-Four AND an Open-Three simultaneously in one move guarantees checkmate because the opponent cannot block both threats!