Reversi

Overview

Black flips to white, white flips to black, and a single move can swing thirty disks at once. Reversi — closely tied to the game sold as Othello — is the flanking game: you place a disk so that a straight line of enemy disks is sandwiched between your new disk and one you already held, and every disk in that line flips to your color. The board starts with a tight four-disk center, and from there the position cascades outward across the eight-by-eight grid until all sixty-four squares are filled or neither side has a legal move. Corners are gold because they can never be flipped back, and edges are nearly as strong, which makes the early and middle game a quiet fight over who gets corner-adjacent squares. The live score tracks the disk count, but the player holding more disks at the end is the one who wins.

How to Play

Click any highlighted cell to place a disk; the green highlights mark every square where a legal flank is available, so you never have to hunt for them. On a touch screen the same move is a tap on the highlighted cell, and the keyboard route is simply clicking a valid cell. After your disk lands, every enemy disk caught in a straight line between the new disk and an existing one of yours flips to your color, and the live score updates on the spot. If you have no legal move the game auto-passes for you, and the end is detected automatically when neither side can play. The computer, which leans toward corner grabs and greedy captures, takes its turn right after yours.

Tips & Strategy

Corners decide the game, so play around them and never hand one to the computer for free. The most common way players lose a corner is by pushing a disk onto the squares next to it — the X-squares and C-squares — which lets the opponent move into the corner on the very next turn. If you must play near a corner, make sure you already hold the corner itself. Mobility matters more than disk count for most of the game: having fewer legal moves than the opponent is usually a worse sign than having fewer disks, because it limits your replies. In the late game, count the empty squares and look for the move that flips the most disks on the final few turns, since the board fills and the score locks in fast.