Reversi
Flip discs, take corners โ versus a corner-savvy AI or a friend.
About this game
Place a disc to flank enemy discs and the whole line flips. Dots mark your legal moves; the AI values corners, avoids the poisoned squares beside them, and weighs mobility โ beatable, but it punishes greed. Two-player mode shares the screen.
The game where less is more
Reversi's beautiful lesson is that early material is a liability: flipping maximum discs each turn fills the board with YOUR discs as flippable fuel while starving you of moves. Strong play optimises MOBILITY โ keep options, deny the opponent theirs โ and banks the only permanent currency: corners, which can never be flipped and anchor whole edges. Hence the other rule the AI respects: the squares adjacent to an empty corner are poison, because playing them hands the corner over. The endgame flips philosophy โ with the board nearly full, raw counting takes over. Brit Lewis Waterman marketed the modern rules in 1883; Japan's Othello variant fixed the four-disc centre start in 1971 and conquered the world. Connect Four and checkers continue the board-game shelf.
Frequently asked questions
Why are corners so valuable?
A corner disc can never be flipped โ no line passes beyond it โ and it anchors stable edges that can't flip either. Games are routinely decided by two or three corners.
Why shouldn't I flip the most discs every turn?
Mid-game discs are ammunition for your opponent โ big flips give them more to flank and fewer moves for you. Mobility (having choices) wins the middlegame; counting wins only the end.
What are the poisoned squares?
The three squares touching each empty corner โ playing them usually gifts the corner. The AI avoids them; learn to feel the same twinge.
Is Reversi the same as Othello?
Same mechanics; Othello (1971) standardised the four-disc starting position and the trademarked name. This is the game everyone means either way.