What are the basic rules of Reversi (Othello)?

On your turn, place a disc of your color on an empty square. The placed disc must outflank one or more opponent discs in a straight line (horizontal, vertical, or diagonal). Outflanking means your new disc and an existing disc of your color form the two ends of a line with only opponent discs between them.

Reversi Rules - How to Play

Goal

Have more discs showing your color than your opponent when the board is full or no more moves are possible.

Overview

Reversi, also known by the trademarked name Othello, is a strategy board game for two players played on an 8x8 uncheckered board. Players place discs that are black on one side and white on the other, flipping opponent's discs to their color by outflanking them.

Setup

Start with four discs in the center: two black and two white, arranged diagonally. Black typically moves first. Each player has a supply of discs (traditionally 32 each, sharing a pool of 64 two-sided discs).

How to play

On your turn, place a disc of your color on an empty square.
The placed disc must outflank one or more opponent discs in a straight line (horizontal, vertical, or diagonal).
Outflanking means your new disc and an existing disc of your color form the two ends of a line with only opponent discs between them.
All outflanked opponent discs in all directions are flipped to your color.
You must make a move that flips at least one disc; if you cannot, you pass your turn.
The game ends when neither player can make a legal move (usually when the board is full).
Each disc flip can trigger additional flips if it creates new outflanking situations - all happen simultaneously on placement.

Winning the game

Count all discs when the game ends. The player with more discs of their color wins. If both have 32, it's a draw. Games are often decided by large margins since a single move can flip many discs.

Strategy tips

Corners are extremely valuable - once captured, they can never be flipped. Prioritize corner control.

Avoid placing discs adjacent to corners early, as this gives your opponent corner access.

Edge squares (especially X-squares diagonally adjacent to corners) are dangerous early in the game.

Mobility (having more move options than your opponent) is often more important than disc count.

Try to force your opponent into making bad moves by limiting their options.

The endgame often reverses earlier positions - don't worry about disc count until late.

Control the tempo by maintaining access to moves while restricting your opponent's.

History

The game originated in England in the 1880s as Reversi. In 1971, Japanese salesman Goro Hasegawa trademarked an enhanced version as 'Othello,' which became extremely popular worldwide.