Technically, as @TheOldReb pointed in rarely occurs in an actual game unless your forcefully create it. There are different ways of checkmate patterns with a B,K and N vs lone K. I use the simplest of those. You get the king to a corner. Ideally, opponent king will try to stay in the center and in the worst scenario, get to the corner square whose color is opposite to that of the bishop. From there, it's relatively easy to force a mate.
Based on FIDE guidelines though, for any random king and two knights versus bare king endgame, the game is won by the side having two knights if the side having only a bare king runs out of time, since technically speaking, checkmate positions are possible. It does not matter whether checkmate can be forced or not. The same goes for king and knight versus king and bishop. Either side can win on time since checkmate positions are possible for both kings.
That's during an OTB game. But Chess.com follows the USCF rules that declare such a situation as a draw.
We discussed about this before... See this thread: https://www.chess.com/forum/view/game-analysis/why-the-game-ends-drawn-in-this-situation
Based on FIDE guidelines though, for any random king and two knights versus bare king endgame, the game is won by the side having two knights if the side having only a bare king runs out of time, since technically speaking, checkmate positions are possible. It does not matter whether checkmate can be forced or not. The same goes for king and knight versus king and bishop. Either side can win on time since checkmate positions are possible for both kings.
That's during an OTB game. But Chess.com follows the USCF rules that declare such a situation as a draw.
We discussed about this before... See this thread: https://www.chess.com/forum/view/game-analysis/why-the-game-ends-drawn-in-this-situation
I know, Chess.com treats king and two knights versus king as drawn, even though checkmate is possible, since there is no reasonable way to force a checkmate without the help of the opponent.
I was wondering, By the same principle, in the following example, there is no reasonable way for Black to win without White giving up his queen to the Black pawn and playing terribly for the remainder of the game, so shouldn't the situation be declared drawn also if White runs out of time? Although we all know that the current rules are that Black wins on time in that situation.
Based on FIDE guidelines though, for any random king and two knights versus bare king endgame, the game is won by the side having two knights if the side having only a bare king runs out of time, since technically speaking, checkmate positions are possible. It does not matter whether checkmate can be forced or not. The same goes for king and knight versus king and bishop. Either side can win on time since checkmate positions are possible for both kings.
That's during an OTB game. But Chess.com follows the USCF rules that declare such a situation as a draw.
We discussed about this before... See this thread: https://www.chess.com/forum/view/game-analysis/why-the-game-ends-drawn-in-this-situation
I know, Chess.com treats king and two knights versus king as drawn, even though checkmate is possible, since there is no reasonable way to force a checkmate without the help of the opponent.
I was wondering, By the same principle, in the following example, there is no reasonable way for Black to win without White giving up his queen to the Black pawn and playing terribly for the remainder of the game, so shouldn't the situation be declared drawn also if White runs out of time? Although we all know that the current rules are that Black wins on time in that situation.
Well, black has mating material with the pawn. The situations are similar, where white would have to help black in order to get the mate, but the site chose to go with the regular rules most of the time without having to come up with scenarios in the less common material combinations to guarantee mate is possible.
There is another recent topic where the FIDE implementation was discussed in some detail.
The Lone King can only be mated on any of the 28 edge-squares.
But mate can only be forced by driving the Lone King to one of only 6 edge-squares: either corner-square of the Bishop's traveling-color or either edge-square next to those.
A computer has done it before but it cannot be done within the 50 move rule ( I think the fastest its ever been done is something like 120 moves
later dudes
A computer has done it before but it cannot be done within the 50 move rule ( I think the fastest its ever been done is something like 120 moves
later dudes
That doesn't sound right. A position that appears with a lone king vs. a k, n, and b could be close to a mate already, or it could be very far. But my guess is that the average would be about 30 moves or so. Even in the optimal position for the lone king, (which probably never happens) it seems like it would still take less than 50 moves.
That would depend where in official tournaments it would be a draw but on chess.com it would be a win
In this situation, unless en passant is possible, neither side will be able to come up with sequences leading to checkmates at all, since the pawns are completely deadlocked and the kings will be too scared to walk into the paths of the pawns (technically speaking, sacrificing a king is the only way for one of the pawns to be able to move again). The outcome should be a draw once this position has been established, regardless of whether either player drops on time or not. I highly doubt Chess.com would rule it as a win though.
This rule overrides the situation where losing on time while the opponent has pawns is a loss. A possible situation of the latter is shown in the diagram that I come up with above, since moving the White queen towards the capturing square of the Black pawn is legal and can be played, and therefore there are ways for Black to checkmate the White king, although most players will probably not sacrifice the White queen. So this essentially simplifies to the rule that the losing side wins if he/she is able to come up with at least one sequence of legal moves to checkmate the other king when the winning side drops his/her flag.
Back to the main topic, in most situations the defending king will be in the centre of the board, and will slowly make its way to the 'wrong' corner of the board (in other words, the corner square that has a different colour from the square that the bishop resides on), since checkmate cannot be forced in this corner, The defending side will aim to prolong the game (by this point he/she will probably not resign, since he/she did not resign at the start of the four pieces endgame in the first place), waiting for the winning side to forcefully send the king to the correct corner.
How useful is it for class players to learn this rare endgame, which even some GMs have failed to win?
Might one's time be better spent on rook and pawn endgames or practicing tactics or studying GM games or honing part of one's opening repertoire?
If one does learn the K+B+N mate, how long does the knowledge stick without refreshing it?
How useful is it for class players to learn this rare endgame, which even some GMs have failed to win?
Might one's time be better spent on rook and pawn endgames or practicing tactics or studying GM games or honing part of one's opening repertoire?
If one does learn the K+B+N mate, how long does the knowledge stick without refreshing it?
Perhaps we now know how to win this endgame because players have studied these positions extensively. Before then, not much was known about this endgame, and several grandmasters are unable to convert this endgame into a win. Now that there are relevant materials and sources that players can search on, most grandmasters should be able to win this endgame.
Learning this endgame, at the very least, adds an extra 'endgame repertoire' into players' knowledge. While other endgames indeed appear on a more frequent and regular basis (such as rook and pawn endgames, knight and pawn endgames, bishop and pawn endgames or even pawn endgames without other pieces), it is still good to know this endgame, just like king and queen versus king and rook endgames. We never know, perhaps one bishop and knight versus lone king endgame might just appear in our next game.
Since this endgame does not appear often, our knowledge of this endgame may fade over time. But, just as we would for school subjects, a small bit of training or exposure to this endgame is sufficient to help us recall the relevant techniques.
A computer has done it before but it cannot be done within the 50 move rule ( I think the fastest its ever been done is something like 120 moves
later dudes
That doesn't sound right. A position that appears with a lone king vs. a k, n, and b could be close to a mate already, or it could be very far. But my guess is that the average would be about 30 moves or so. Even in the optimal position for the lone king, (which probably never happens) it seems like it would still take less than 50 moves.
I would need to look it up but I believe from the worst case scenario, mate is forced in 32 moves or less, with perfect play.
In this situation, unless en passant is possible, neither side will be able to come up with sequences leading to checkmates at all, since the pawns are completely deadlocked and the kings will be too scared to walk into the paths of the pawns (technically speaking, sacrificing a king is the only way for one of the pawns to be able to move again). The outcome should be a draw once this position has been established, regardless of whether either player drops on time or not. I highly doubt Chess.com would rule it as a win though.
This rule overrides the situation where losing on time while the opponent has pawns is a loss. A possible situation of the latter is shown in the diagram that I come up with above, since moving the White queen towards the capturing square of the Black pawn is legal and can be played, and therefore there are ways for Black to checkmate the White king, although most players will probably not sacrifice the White queen. So this essentially simplifies to the rule that the losing side wins if he/she is able to come up with at least one sequence of legal moves to checkmate the other king when the winning side drops his/her flag.
It would be a win here. The site doesn't check for anything but material at flag fall.
Perhaps we now know how to win this endgame because players have studied these positions extensively. Before then, not much was known about this endgame, and several grandmasters are unable to convert this endgame into a win. Now that there are relevant materials and sources that players can search on, most grandmasters should be able to win this endgame.
eric0022: This endgame has been mapped out for a long time. Certainly it was covered in Fine's "Basic Chess Endings" published in 1941. Masters and grandmasters who have failed to mate either didn't bother learning it or they did and it didn't stick or they were in too much time pressure.
Jeremy Silman didn't include K+B+N in his endgame book because:
...mastering it would take a significant chunk of time. Should the chess hopeful really spend many of his precious hours he's put aside for chess study learning an endgame he will achieve (at most) only once or twice in his lifetime?
Which is my view though I lack Silman's cred to say so.
Perhaps we now know how to win this endgame because players have studied these positions extensively. Before then, not much was known about this endgame, and several grandmasters are unable to convert this endgame into a win. Now that there are relevant materials and sources that players can search on, most grandmasters should be able to win this endgame.
eric0022: This endgame has been mapped out for a long time. Certainly it was covered in Fine's "Basic Chess Endings" published in 1941. Masters and grandmasters who have failed to mate either didn't bother learning it or they did and it didn't stick or they were in too much time pressure.
Jeremy Silman didn't include K+B+N in his endgame book because:
...mastering it would take a significant chunk of time. Should the chess hopeful really spend many of his precious hours he's put aside for chess study learning an endgame he will achieve (at most) only once or twice in his lifetime?
Which is my view though I lack Silman's cred to say so.
I have to agree though that it is not easy to master this endgame. A fairly large amount of time is required in this endgame.
I only learned this endgame because this endgame was included as part of my endgame training on another website a few months ago, or I would probably be clueless on the techniques also.
I think at the grandmaster level though, gaining rating points are something extremely difficult to achieve, but losing rating points are much easier. Thus, perhaps knowing this endgame would save grandmasters from losing unnecessary rating points (or gaining fewer rating points if the opponent is higher rated because of a draw) by obtaining a win.
In this situation, unless en passant is possible, neither side will be able to come up with sequences leading to checkmates at all, since the pawns are completely deadlocked and the kings will be too scared to walk into the paths of the pawns (technically speaking, sacrificing a king is the only way for one of the pawns to be able to move again). The outcome should be a draw once this position has been established, regardless of whether either player drops on time or not. I highly doubt Chess.com would rule it as a win though.
This rule overrides the situation where losing on time while the opponent has pawns is a loss. A possible situation of the latter is shown in the diagram that I come up with above, since moving the White queen towards the capturing square of the Black pawn is legal and can be played, and therefore there are ways for Black to checkmate the White king, although most players will probably not sacrifice the White queen. So this essentially simplifies to the rule that the losing side wins if he/she is able to come up with at least one sequence of legal moves to checkmate the other king when the winning side drops his/her flag.
It would be a win here. The site doesn't check for anything but material at flag fall.
A bit unusual for the website to declare the deadlocked position won by one side because of time though.
not super hard, but also not easy to do if (in 50 moves) if you have not worked on it and solved it at home. by the way does anyone know if the chess.com live games consider K+N+N vs K a draw if your time runs out?
later dudes
Who is holding on to the two knights? It could be the case where you have the two knights but you run out of time. Of course in that case, the enemy, having only a lone king, does not have sufficient material to checkmate your king, and hence the game is drawn.
Instead, if the side having the bare king runs out of time, it should be a draw on an online Chess.com game, but it is a win on an over-the-board game according to the FIDE rules, since strictly speaking it is possible (although extremely unlikely since mate cannot be forced) to come up with a legal sequence of moves to checkmate the lone king.
If I read your comments correctly did you say the side with the lone king should get a win in an over the board game? I agree that it's possible for two knights to win, even a forced win, because it's possible that the capture move that leaves just two lone knights could end up in a forced mate position. Probably never happen though, but possible.
Those were good tactics from you. I wrote that paragraph in a rather ambiguous phrasing. Of course we know what I mean.
It's possible that the knight which makes a capture happens to also land a checkmate, although very uncommon.
Based on FIDE guidelines though, for any random king and two knights versus bare king endgame, the game is won by the side having two knights if the side having only a bare king runs out of time, since technically speaking, checkmate positions are possible. It does not matter whether checkmate can be forced or not. The same goes for king and knight versus king and bishop. Either side can win on time since checkmate positions are possible for both kings.