https://www.chess.com/puzzles/problem/1250705
The following puzzle was one I just got and, unfortunately, got incorrect according to the tactic itself. The proposed solution is
1. Kh2 Qf5 2. c7 Qc8 3. d6 Ke8 4. Rb5, when Rb8 is unstoppable. I can say that this is definitively winning, and I agree this is a valid solution. I, however, found another completely winning solution that the computer fails to see because it's a long term plan that black can do nothing about, meaning it's outside the scope that the depth of the engine finds. It wins just as easily though--I managed to cleanly win against the computer in the position.
As an alternative to 3. d6, all of Rc6, h4, b4 and a variety of other moves win just as easily. Easiest, however, is starting with Rc6, since it's a key move in all the variations (although not even strictly necessary, since white can get black in zugzwang to make the king give up ground for a much later Rc6, but that's aside from the point). The idea is simple: black cannot move, and b4-5, a4-5, b6 followed by b7 will eventually win. In the meantime, white has all the time in the world to improve their kingside pawns and king positioning to make the endgame trivial. I was able to easily beat Stockfish with this move and this idea, so I do believe it is valid, seeing as both me and the computer cannot find a refutation.
Because the puzzle seems to have multiple solutions that are trivially winning, even though the given solution wins faster, I do not believe this is a good puzzle to keep on the site, since both solutions give black no chance to get back into the game, and so they seem to be equally valid.
Generally speaking, the fastest move is considered best. I ask about this one. Staff may remove it or cut it off at c7
https://www.chess.com/puzzles/problem/1250705
The following puzzle was one I just got and, unfortunately, got incorrect according to the tactic itself. The proposed solution is
1. Kh2 Qf5 2. c7 Qc8 3. d6 Ke8 4. Rb5, when Rb8 is unstoppable. I can say that this is definitively winning, and I agree this is a valid solution. I, however, found another completely winning solution that the computer fails to see because it's a long term plan that black can do nothing about, meaning it's outside the scope that the depth of the engine finds. It wins just as easily though--I managed to cleanly win against the computer in the position.
As an alternative to 3. d6, all of Rc6, h4, b4 and a variety of other moves win just as easily. Easiest, however, is starting with Rc6, since it's a key move in all the variations (although not even strictly necessary, since white can get black in zugzwang to make the king give up ground for a much later Rc6, but that's aside from the point). The idea is simple: black cannot move, and b4-5, a4-5, b6 followed by b7 will eventually win. In the meantime, white has all the time in the world to improve their kingside pawns and king positioning to make the endgame trivial. I was able to easily beat Stockfish with this move and this idea, so I do believe it is valid, seeing as both me and the computer cannot find a refutation.
Because the puzzle seems to have multiple solutions that are trivially winning, even though the given solution wins faster, I do not believe this is a good puzzle to keep on the site, since both solutions give black no chance to get back into the game, and so they seem to be equally valid.