Learn Renju: Tutorial

Black places the first stone, typically near the center of the board for maximum influence. White responds, and turns alternate.

Stones cannot be moved or removed once placed. The board gradually fills up over the course of the game.

In this position, a few opening moves have been played near the center.

The primary win condition is getting exactly 5 stones in an unbroken line -- horizontally, vertically, or diagonally.

Black must get EXACTLY 5 (not 6 or more). White can win with 5 or more in a row.

In this position, Black has just completed 5 in a row horizontally and wins.

An overline is 6 or more stones of the same color in a row. For Black, an overline is FORBIDDEN -- Black must make exactly 5, not more.

If placing a Black stone would create 6+ in a row without also creating exactly 5 in another direction, the move is illegal.

White is NOT restricted by this rule. White can win with 5 or more in a row.

This rule is part of what balances Black's first-move advantage.

A double-four is when a single move creates two separate lines of exactly 4 stones that can each become 5. For Black, this is FORBIDDEN.

A "four" is a row of 4 stones where adding one more would create exactly 5. If one move creates two such fours simultaneously, Black cannot play it.

This restriction does not apply if the move also makes exactly 5 in a row (which would be a winning move).

White has no such restriction.

A double-three is when a single move creates two "open threes" simultaneously. For Black, this is FORBIDDEN.

An open three is a row of 3 stones with both ends open that can become a "straight four" (4 in a row with both ends open, guaranteeing a win).

This is the most common restriction Black faces. Like double-four, it does not apply if the move directly creates exactly 5 in a row.

White can freely create double-threes.

White has NO forbidden moves. White can create double-threes, double-fours, and overlines freely.

White can even win with 6+ in a row. This asymmetry compensates for Black's advantage of moving first.

White's strategy often involves forcing Black into positions where available moves are limited by the forbidden move rules.

A draw occurs when the entire board is filled and neither player has achieved 5 in a row.

A draw can also occur if Black has no legal moves remaining (all empty positions are forbidden). This is extremely rare.

In practice, draws are uncommon in Renju because the board is large and the forbidden move rules create tactical imbalances.

Key strategic concepts in Renju:

- Black should aim for forcing sequences ("VCT" and "VCF") that lead to an unstoppable 5. Be mindful of forbidden moves when setting up threats.

- White should try to exploit Black's restrictions. Force Black into positions where the best response would be a forbidden move.

- Control the center: Stones near the center exert more influence across the board.

- Build multiple threats: Create two simultaneous threats that your opponent cannot both block (without triggering forbidden rules for Black).