Games

Reversi

The classic game of discs that change colour: bracket a row of your opponent’s discs and they all turn to yours. Play the computer at five levels, from a beginner who blunders corners to a master that solves the last twenty moves exactly, play a friend at the same table, or watch the computer play itself.

By Mykhailo Makarov

Actual application image

What happens

Place a disc so that a straight line of your opponent’s discs lies between it and one of your own – across, down or diagonally; every such line turns to your colour. Black begins. A side that cannot turn anything passes, and the game ends when neither side can move: the most discs wins. The computer searches with alpha-beta, iterative deepening and a transposition table, weighing mobility, frontier, corners and the squares that give them away, stable discs and the worth of each square; near the end it plays the remaining moves out exactly – from twenty empty squares at the master level. The weaker levels pick among the moves close to the best, so their mistakes are plausible ones.

Try this

Click a marked square to place a disc. Turn the table with the right mouse button, zoom with the wheel.

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