Reversi

How to play Reversi

Finish with more discs than your opponent. You are obsidian (dark); The Explorer is ivory (light). The board starts with two discs each. Obsidian plays first.

1. Choose a marked empty square. Your new disc must trap one or more ivory discs in a straight line between it and another obsidian disc.
2. Every trapped disc flips. Lines can run horizontally, vertically or diagonally. A single move can flip discs in several directions. There must be no gaps.
3. Turns alternate. If a player has no legal move, that player automatically passes. A pass is required only when there is no legal move.
4. The game ends when neither player can move. This can happen before the board is full. Whoever has the most discs wins; equal totals are a draw.

Place obsidian at + to flip both ivory discs.

Three-minute mode: each side has three minutes, with no added time. Your clock starts when you select the mode or start a timed game. Running out of time loses the game, regardless of disc totals. Time continues while these notes are open or you leave the tab.

Field tip: corners cannot be flipped. Taking the most discs early is not always the best move.