How many discs do you start with in reversi?

Four are on the board before anyone moves — two of each colour, in the middle, on opposite diagonals. Every move after that adds exactly one disc, so a game places at most 60 more.

Do you have to make the move that flips the most discs?

No, and you usually should not. Any legal move is allowed, and the move that flips fewest discs is very often the strongest one because it leaves your opponent the least to work with.

What is the difference between reversi and checkers?

Only the board. In [checkers](/checkers) you move and capture pieces that stay yours; in reversi you never move a disc once it is placed, and every disc on the board can change owner many times.

Can you lose reversi by having too many discs?

Not directly — the count at the end is all that matters. But leading on discs in the midgame usually means fewer legal moves and more discs exposed to attack, so it is a warning sign rather than a lead.

How to Play Reversi

Reversi is played on an 8 × 8 board by two players, dark and light. Four discs start in the centre in a diagonal cross and dark moves first. On your turn, place a disc so it traps a line of your opponent's discs against one of your own; every trapped disc flips. If you have no legal move you are skipped. When neither player can move, whoever has more discs wins.

The rules, step by step

1Set the opening crossFour discs go in the four central squares, each colour on one diagonal, before anyone moves. Dark plays first.
2Trap a line to place a discPlay on an empty square so an unbroken run of your opponent's discs lies between the new disc and one of yours, in any of the eight directions.
3Flip everything you trapped, onceEvery disc in every run you closed turns over. Discs flipped this move do not go on to trap anything else — there is no cascade.
4A move has to flip somethingIf a square traps no run of enemy discs it is not a legal move, however many enemy discs happen to be next to it.
5A player with no legal move is skippedPassing is compulsory and automatic, never a choice. The other player moves again, and the game continues.
6Count the discs when neither side can moveThat is the end of the game, whether or not the board is full. The player with more discs on the board wins; equal counts are a draw.

Try it — the rules above, running

You2Light2Empty60Time0:00LevelMedium

New game starts a fresh board with you playing Dark and moving first. Click one of the ringed squares to place a disc; hovering one shows exactly which discs it would flip. Hint names the strongest square and the reason, and the opponent’s strength lives in the ⋯ menu. If you have no legal move you are skipped automatically — that is the rule, not a bug.

Your statistics · Medium

Played: 0
Won: 0
Win rate: 0%
Streak: 0
Best streak: 0
Best time: —

Four plies of corners, mobility and frontier; the last 10 squares solved exactly.

Keyboard

Arrows: Move the focus cursor
Enter / Space: Place a disc
H: Hint
N: New game
F: Full screen

How does a single reversi move work?

1Find an empty square next to an enemy discOnly empty squares can be played, and a square with no opponent disc beside it can never trap anything.
2Look along that direction for one of your own discsRead outward from the empty square: one or more enemy discs in an unbroken run, then a disc of your colour. That is a trap, and it is what makes the move legal.
3Check the other seven directions tooOne move can close runs in several directions at once, and every run it closes flips. Checking all eight is how you find the move that flips six discs instead of one.
4Place the disc and flip what you trappedThe trapped discs turn over to your colour. Nothing else changes — the discs that just flipped do not trap anything further this move.

What makes a placement illegal?

The square is not empty. You never move a disc that is already down, and you never remove one.
The run is not closed. Enemy discs leading to an empty square, or running off the edge of the board, trap nothing.
Your own disc is adjacent. With no enemy disc between the two of yours there is no run to flip, so there is no move.
Nothing at all would flip. This is the single rule that catches people out: touching an enemy disc is not enough on its own.

When do you pass in reversi?

Only when you have no legal move anywhere, and then you have no say in it. Your opponent plays again and you rejoin as soon as a square opens up for you. You never pass voluntarily, you never lose your turn permanently, and the game does not end because one player is stuck — it ends when both are.

How does a game of reversi end?

When neither player has a legal move. Usually that is a full board — four discs start on it and at most 60 more are placed, one per move — but a game can finish early if both sides run out of options, and it can finish very early indeed if one colour is wiped off the board entirely.

Count the discs. More discs wins; an equal count is a draw. Competition scoring credits any empty squares to the winner so that the two scores add to 64, which changes the margin but never who won.

How do you win more often?

Take corners, and refuse to give one awayThe four corners are the only squares that can never be flipped, and each one anchors the two edges leading away from it. The price of a corner is usually paid earlier, on one of the four X-squares or eight C-squares that touch it — leave those alone while the corner beside them is empty.
Count your opponent's replies, not your own discsA position where your opponent has three legal moves and you have twelve is winning almost regardless of the disc count, because they will shortly be forced to play a square they do not want. This is exactly what the opponent on this page optimises for, at full weight, until the last twenty squares.
Play the smallest flip that does the jobFlipping six discs usually puts six more of your discs next to empty squares, which is six more things your opponent can attack. Quiet moves that turn over one or two discs deep inside your own shape keep your position out of reach and keep your options open.
Only start counting discs in the last twenty squaresMaterial is worth nothing while there is still manoeuvring to do and worth everything at the end, which is why the evaluation here gives disc difference zero weight until fewer than 20 empty squares remain and full weight on the final placement. Switch your own thinking at roughly the same point.
An edge is not a cornerSixteen of the twenty-eight edge squares are genuinely safer than the middle, because an edge disc has five neighbours rather than eight. The other twelve — four corners and eight C-squares — are a separate question entirely, and taking a C-square to reach an edge is how most beginners lose the corner beside it.

Common questions about reversi

How many discs do you start with in reversi?: Four are on the board before anyone moves — two of each colour, in the middle, on opposite diagonals. Every move after that adds exactly one disc, so a game places at most 60 more.
Do you have to make the move that flips the most discs?: No, and you usually should not. Any legal move is allowed, and the move that flips fewest discs is very often the strongest one because it leaves your opponent the least to work with.
What is the difference between reversi and checkers?: Only the board. In checkers you move and capture pieces that stay yours; in reversi you never move a disc once it is placed, and every disc on the board can change owner many times.
Can you lose reversi by having too many discs?: Not directly — the count at the end is all that matters. But leading on discs in the midgame usually means fewer legal moves and more discs exposed to attack, so it is a warning sign rather than a lead.

Ready to stop reading? Play reversi on the full board, with controls and statistics tailored to that game.