Originally posted by VarenkaIf he had just asked, "Hey people, I was wondering... it is possible to mate KN x K?", the story would have been another... 🙂
The thread in question was discussing a specific game. From the initial poster's point of view it was being referenced. He wasn't asking a general question; he wanted help with his specific game.
the question wasn't a theoratical one. if he had asked "my opponent has a h pawn and a light squared bishop and I'm playing black, there's nothing else left on the board, is this position drawn?" no one should answer that, since with bad defense anything can happen. but the position he asked was offically drawn. it's like asking "my opponent is saying something like 'stalemate', is it really a draw?" so there's no harm in answering that.
Originally posted by diskamylIts only a draw if you cannot win even with the most inept play from your opponent.
the question wasn't a theoratical one. if he had asked "my opponent has a h pawn and a light squared bishop and I'm playing black, there's nothing else left on the board, is this position drawn?" no one should answer that, since with bad defense anything can happen. but the position he asked was offically drawn. it's like asking "my opponent is saying something like 'stalemate', is it really a draw?" so there's no harm in answering that.
In such circumstances answering the question jeopadises no one and save both hours of agony.
The only positions that come into this category are K&N vs K and K&B vs K as a single pawn is always enough to win against inept play as is 2Ns. Of course K&2B or K,B&N wins even against best play and there are no other certain draws.
Originally posted by lauseyIf there is a pawn on the board, there is sufficient material (theoretical draws are a different sort than those declared draws by the rules).
If you asked, "Is it possible to mate KBP vs K?" though, it doesn't matter if the game is in progress, because no positions are mentioned. It is a general question with a given set of pieces. In this case the answer will be "It depends on the position".
The USCF rules--which do not govern events outside the United States, but are still a reasonable benchmark for examining gaps in the RHP rules--clearly state that two knights against a lone king is a draw if the weaker side's clock expires (14E3), as well as a single knight or bishop (14E2).
The player in the closed thread framed his question as if seeking advice (inappropriate), but also asked a question that concerns a rule of insufficient material (which should be implemented in some way here). His opponent sought a draw because the game was drawn, or so it seems from the poster's original statement.
In KN v K, I would think either side could claim the draw without the other side being able to reject it, by the reasoning that no mating position can be constructed at all
As far as I know, there are only 3 scenarios where a draw can be claimed.
1) KN v K
2) KB v K
3) K v K
A rook or queen can give mate with the king's help and a pawn can promote.
A pawn can promote to a queen or rook.
There are known patterns for forced mate with 2 bishops and KBN.
And while 2 knights is almost always theoretically drawn, it is possible to construct a checkmate position.
Oddly enough, positions can be constructed for KN v KN, KB v KN, and opposing bishops of opposite color for which the king, trapped by his own piece in the corner, is mated.
I can't think of one offhand for opposing bishops of the same color.
Originally posted by geepamoogleThis is drawn as (assuming a king is in a corner square of the same colour as the bishops, the only position there could be any chance of a mate) the two squares adjacent to the king cannot both be controlled by the opposing king.
I can't think of one offhand for opposing bishops of the same color.
In that case, there are 4 scenarios that could be determined as "drawn by insufficient material", or that mate is impossible to set-up no matter how bad the enemy blunders, and hence worthy of a claimed draw.
1) Lone kings
2) KN v K
3) KB v K
4) KB v KB (IF bishops can threaten each other)
There are 4 scenarios I can think of where a draw should be accepted if offered, because mate would practically always necessitate the mated side making an obvious blunder. However, because a mate possibility exists, they don't qualify for a claimed draw by insufficient material.
1) KNN v K (only side with 2 knights can mate.)
2) KN v KN
3) KB v KN
4) KB v KB (IF neither bishop can attack the other bishop)