Reversi

Goal

Finish with more discs of your colour when neither player can move.

What makes a legal placement?

Dark starts from the four center discs. Click, tap, or use arrows and Enter on a legal empty square. A move must enclose at least one opposing disc between the new disc and another of your discs. Every continuous enclosed line flips, horizontally, vertically or diagonally. Empty squares and your own discs stop a line; flips do not cause chain reactions.

Why are corners useful?

One placement can flip in several directions. A corner disc cannot be enclosed by the opponent and remains yours. Other discs can change color repeatedly; placed discs never slide to another square.

When does the game end?

Players alternate unless the next player has no legal move. That turn passes automatically; you cannot choose to pass when a move is available. When neither player can move, more discs wins and equal totals draw, even if empty squares remain.

What changes with the opponent or difficulty?

Play against the computer or share the board with another person. Difficulty changes computer choices; all modes use the same 8 by 8 board, flipping rules and disc-count ending.

Can I flip across a gap?

No. An enclosed opposing line must be continuous. An empty square or one of your own discs stops it. Newly flipped discs do not cause a chain reaction.