Explanation
Open the explanation (shows the answer)
The answer is b7. With best play to the end: ±0 (a draw).
Best line: b7 h5 b2 h4 g3 a1 b1 h3 h2 g4
Other moves
| Move | Result | Why |
|---|---|---|
| g2 | -6 (a loss by 6) | g2 is an X-square (diagonal to the corner h1). While the corner is empty it tends to give the corner away. Opponent's moves: 8 after this move, 6 after b7. Openness: 3 for this move (flips 4), 0 for b7 (flips 2). The opponent's best answer is h5 (then b2 g4 b7). |
| b2 | -10 (a loss by 10) | b2 is an X-square (diagonal to the corner a1). While the corner is empty it tends to give the corner away. After this move the opponent can play the corner a1. The opponent's best answer is b7 (then g3 h5 h4). |
| g3 | -10 (a loss by 10) | Opponent's moves: 9 after this move, 6 after b7. Openness: 2 for this move (flips 1), 0 for b7 (flips 2). The opponent's best answer is b7 (then b2 h5 h4). |
| h5 | -14 (a loss by 14) | The opponent's best answer is b7 (then b2 g4 g3). |
| g1 | -14 (a loss by 14) | Opponent's moves: 8 after this move, 6 after b7. Openness: 2 for this move (flips 4), 0 for b7 (flips 2). The opponent's best answer is b7 (then h5 h4 g3). |
About these puzzles
Each position comes from a real game. The engine solved it to the end (perfect play by both sides) and only positions with a single best move, clearly better than the second-best move, were kept. "Best play wins by N" is the final disc margin when both sides play perfectly.
If you play a different move, you see the final margin your move leads to with perfect play afterwards, and how much it gave up. Results are stored only in this browser.
To be graded during a full game, go to the Reversi dojo.