Play Reversi Online for Free
Reversi looks deceptively simple: a near-empty 8×8 board, two starter discs each, and a single move type. But the moment you outflank your first row, you discover the twist that makes this game brutal — every disc you own can be stolen back, and the player ahead at move 30 often loses at move 60. On Classic Play you place discs to bracket and flip your opponent's, fighting for the four unflippable corners while denying them yours. Black always moves first, and one careless square next to a corner can hand the whole game away.
How to Play Reversi
Reversi is played on an 8x8 board that starts with four discs locked in the centre: two white on one diagonal and two black on the other. Black always moves first. On your turn you place one disc on an empty square so that it traps at least one straight, unbroken line of your opponent's discs between the disc you just placed and another disc of your own colour. Lines can run horizontally, vertically, or diagonally, and a single placement can flip in several directions at once.
Every opponent disc caught between your two discs flips to your colour immediately. A move is only legal if it flips at least one disc, so you can never simply 'pass to a quiet square' — if you have any flipping move available, you must make one. If you have no legal move at all, your turn is skipped automatically and your opponent plays again. The game continues until neither player can move, which is usually but not always when all 64 squares are filled.
When neither side has a legal move, the discs are counted: whoever owns more discs wins, and an equal count is a draw. Against the computer you can choose Easy, Medium, or Hard, and an undo button lets you take moves back while you are learning the flipping patterns.
Playing Against the Computer
All three levels judge a position the same way: corner control, mobility, a disc-count term that grows as the board fills, and a positional square table that scores a corner at +100, with an extra bonus for holding it, the squares diagonally next to a corner at -40, and the edge squares beside a corner at -20. Each level thinks for a limited time on each move. Easy thinks briefly and picks at random among its four best moves, Medium thinks longer and picks between its two best, and Hard thinks longest, always plays the best move it finds, and once few squares remain reads the game to its end. Beating Hard means genuinely managing mobility rather than grabbing discs, and building your lead before those final moves.
Frequently Asked Questions
Who moves first in reversi, and does it matter?
Black always moves first here, matching standard Othello rules. Moving first gives no real edge: a computer analysis published in 2023 reported that perfect play by both sides ends in a draw, and among human players the difference is minor.
Can I pass my turn if I don't like any of my moves?
No. You may only pass when you have zero legal flipping moves, and the engine does that automatically by skipping you. If even one move that flips a disc exists, you are forced to play it, so you cannot deliberately sit out a turn.
Why is having more discs in the middle of the game often bad?
Because discs flip back and forth, an early lead is unstable and tends to shrink your mobility — owning more squares leaves you fewer empty cells to play into. Strong play means flipping few discs early to keep options open, then flipping aggressively only in the final ten to fifteen moves.
What are X-squares and C-squares, and why avoid them?
X-squares are the four squares diagonally next to a corner (like b2); C-squares are the edge squares one step from a corner (like a2). Playing either usually lets your opponent drop straight into the adjacent corner, which can never be flipped back, so avoid them unless that corner is already safely yours.
Does the game always end with the board full?
Not necessarily. The game ends as soon as neither player has a legal move, which can happen before all 64 squares are filled. Empty squares left at the end simply count for nobody — only the discs on the board are tallied, and the higher count wins.