Reversi
Place black and white stones, flanking your opponent to flip their stones to your color. Play the computer and find out why corners matter and why the squares next to them are risky.
Tap a square to place your stone.
2 - 2 You are Black.
How to play
Tap an empty square to place a stone. The faint dots show where you can play. Any enemy stones you flank between your new stone and another of yours turn to your color, in any row, column or diagonal. If you cannot play, you pass automatically. When neither side can play, the game ends and whoever has more stones wins. "Hint" shows the best square by the current evaluation, with the reason, and "Auto-play" lets the computer play both sides until the result. Pick the strength and who moves first below.
Learn more
A corner square can never be flanked from any direction, so a corner, once taken, is yours for good. Squares diagonally or edge-adjacent to a corner, on the other hand, make it easier for your opponent to take that corner. At "Strong", the computer scores positions by these corner and edge values plus how many moves each side has available, and looks ahead for as long as its time budget allows (near the end it can search all the way to the final result). "Normal" looks two moves ahead; "Easy" picks a legal square at random. The 6×6 board is a shorter starter version.