Othello

1 Overview

Othello (also known as Reversi) is a 2-player abstract strategy game played on an 8×8 board with 64 double-sided discs — black on one side, white on the other. Players take turns placing discs and flipping their opponent's pieces. The goal: have more discs showing your color when the game ends.

Othello is famously simple to learn but has extraordinary strategic depth. The official tagline — "a minute to learn, a lifetime to master" — is apt: grandmaster-level play involves long-term positional thinking similar to chess.

2 Setup

Place the board so each player has a light square in the lower-right corner. Set up the starting position in the center four squares: two white discs and two black discs arranged diagonally (white on d4 and e5, black on d5 and e4 — or the mirror image).

Black always goes first. Each player receives 32 discs.

3 Gameplay

On your turn, place one disc of your color on an empty square such that you outflank at least one of your opponent's discs. "Outflanking" means your new disc and one or more of your existing discs sandwich a straight line (horizontal, vertical, or diagonal) of opponent discs with no gaps.

All outflanked discs are flipped to your color immediately. You can outflank in multiple directions at once — all qualifying opponent discs in all directions flip.

If you have no legal move, you must pass. Play continues until neither player has a legal move or the board is full.

4 Legal Moves & Flipping

A move is legal only if it outflanks at least one opponent disc. You cannot play on an occupied square. You cannot play without flipping at least one disc.

• Directions: Outflanking can happen horizontally, vertically, or diagonally — all 8 directions are valid.
• Multiple lines: One placement can outflank in several directions simultaneously. All qualifying discs flip.
• No gaps: The line of opponent discs must be continuous — no empty squares allowed in the middle.
• Forced pass: If you have no legal move, say "pass" and your opponent plays again. If both players must pass, the game ends.

5 End Game & Scoring

The game ends when the board is completely full, or when neither player can make a legal move. Count the discs of each color showing face-up. The player with the most discs of their color wins.

If both players have 32 discs, the game is a draw. In tournament play, ties are broken by prior game results or overtime.

6 Strategy Tips

Corners Are King

Corners cannot be flipped once captured — they are permanent. Fight hard for corners. Avoid placing discs adjacent to empty corners (c1, a3, etc.) — these "X-squares" and "C-squares" give your opponent a path to the corner.

Fewer Discs Early = More Control

Counterintuitively, having fewer discs in the midgame is often stronger. Fewer discs means your opponent has fewer flip targets and you retain more mobility. Don't chase maximum flips every turn.

Mobility Wins

Maximize the number of legal moves you have while minimizing your opponent's options. A player with many moves can dictate the pace; a player with few moves is forced into bad positions.

Edge Squares

Edge squares (non-corner) are stable only when the entire edge is filled. Avoid them early — they can create "wedges" that let your opponent grab a corner.