Reversi (Othello) — Strategy

Black may play a1 or h8, and in this manner, he may play all the remaining moves (since white must pass after each move), for a final score of 40-24 for black! It's therefore clear that having lots of discs, even very close to the end of the game, does not absolutely guarantee an ultimate victory. In the example of Diag. 1, white indeed has many discs, but they are vulnerable: they can be flipped back by the opponent. What's important is therefore not to have many discs but rather to have many discs which can not be flipped back by the opponent, no matter what happens for the rest of the game. Such discs are called "stable discs". Of course, it's often very difficult to acquire stable discs before the last few moves of the game, but first let's see some examples of stable discs.