Explanation
Open the explanation (shows the answer)
The answer is b2. With best play to the end: +10 (a win by 10).
Best line: b2 b1 a2 c3 a1 c2 c1 d2 e1 d1
Other moves
| Move | Result | Why |
|---|---|---|
| a2 | -2 (a loss by 2) | The opponent's best answer is c3 (then b2 c2 c1). |
| e1 | -10 (a loss by 10) | The opponent's best answer is d1 (then a2 c3 b2). |
| c2 | -10 (a loss by 10) | Opponent's moves: 5 after this move, 2 after b2. The opponent's best answer is b1 (then c3 d2 c1). |
| d1 | -12 (a loss by 12) | The opponent's best answer is e1 (then b2 c1 c2). |
| d2 | -14 (a loss by 14) | The opponent's best answer is c3 (then c2 c1 e1). |
| c3 | -16 (a loss by 16) | Opponent's moves: 4 after this move, 2 after b2. The opponent's best answer is d2 (then e1 d1 pass). |
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.