Explanation
Open the explanation (shows the answer)
The answer is d2. With best play to the end: ±0 (a draw).
Best line: d2 a5 b4 a3 a7 c1 a2 b1 b2 a1
Other moves
| Move | Result | Why |
|---|---|---|
| b4 | -4 (a loss by 4) | The opponent's best answer is d1 (then e1 a5 c1). |
| a5 | -10 (a loss by 10) | Opponent's moves: 10 after this move, 8 after d2. The opponent's best answer is a7 (then d2 b3 b4). |
| a7 | -22 (a loss by 22) | Openness: 3 for this move (flips 6), 0 for d2 (flips 1). The opponent's best answer is a5 (then b4 e1 d1). |
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.