goodknight0badbishop - knowing how isn't good enough over the board
Question: Can you mate with just a Knight + Bishop?
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Sep 16, 2017
0
#123
Estrinian wrote:
What do you mean it's not good enough over the board?
goodknight0badbishop - knowing how isn't good enough over the board
Sep 17, 2017
0
#125
I originally learned the N + B mate with Reuben Fine's "Basic Chess Endings" which is not the clearest explanation, but it was good enough and I have enjoyed demonstrating it from time to time.
The explanation in Jesus de la Villa's 100 Endgames You Must Know is the best I've seen - it gives 10 general points compared to 4 in Seirawan's Winning Chess Endings, and it gives you patterns like this to show you what you want to achieve as push the opponent's King to the edge of the board then herd him to the corner with the same color your bishop travels on:
It is easy to avoid this ending.
Sep 21, 2017
0
#127
greersome wrote:
One of the scenarios I am allowed to study using my Fritz 9's endgame training mode is Knight, Bishop, King vs. lone King.
Interestingly enough, the Fritz 9 tutor doesn't actually provide me with any instruction or tutorial. I just move around the board unable to mate. Asking the computer to provide hints doesn't mate, nor does allowing the computer to play against me when I'm the lone king.
Is there a mate possibility for this? What is it?
Also, for anyone else out there, can someone tell me why Fritz9 won't actually teach me anything? That is why I bought it.
If you want to learn how to mate in this ending, I would seriously suggest working out a method yourself rather than looking at any published material.
Published material generally shows an analysis of a couple of positions together with generalities about how to play (some of which are just bad advice). This probably doesn't amount to a method of the kind you want.
What you are probably looking for is a "mindless" method of playing the knight and bishop from any won position, similar to what I would imagine you already know for endings like rook and king against king or rook and two opposite coloured bishops against king.
This is the way I learned the ending. It took a weekend to come up with the method, but another week of evenings and another weekend to dot the t's and cross the i's.
The method doesn't have to be optimal so long as it produces a mate within 50 moves from any won position.
If you decide you have a method, you need to prove that any position for which the method doesn't work is drawn. (This should give you a criterion for determining when a position is drawn - but these are all pretty obvious if you come across them in play.)
When I worked out a method, I spent the first half of the Saturday looking at the king and bishop against king ending. This is a good start.
(You don't need to be any good at chess to work out a method, by the way. Your FIDE rating is probably irrelevant.)
In 40 years of competitive chess I have never had to play this ending.
Sep 21, 2017
0
#130
likesforests wrote:
With the worst starting position and perfect defense mate takes 33 moves. But on average, it only takes 15-20 moves. You can make a few mistakes and still win.
33 moves for the stronger side with either side to play is correct, but an average of 15-20 is very optimistic. According to Wilhelm/Nalimov the average is just short of 26.
spokebloke wrote:
If you search online you can find the pattern. If I remember right it can take as long as 40 or 60 moves though if defended against properly. 2 Bishops is pretty easy.
It's funny that two bishops are usually superior to a rook - but while K+2 B vs K is not difficult, it is somewhat tedious, whereas K+R vs K is quick and easy.
lfPatriotGames wrote:
eric0022 wrote:
goommba88 wrote:
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.
But if the capture move results in king and two knights in a forced mate position, another piece was necessary to create the forced mate. The king and two knights alone could not have achieved a forced mate otherwise. The fact that the other piece is no longer on the board is irrelevant; the forced mate would've been impossible without it.
What if I sacrifice my queen, forcing the opposing king to take it on the corner square and then I mate next move with one of my two knights? That's a forced mate but it's not forced by the king and two knights. The queen sacrifice forced the mate.
Sep 22, 2017
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#134
FBloggs wrote:
What if I sacrifice my queen, forcing the opposing king to take it on the corner square and then I mate next move with one of my two knights? That's a forced mate but it's not forced by the king and two knights. The queen sacrifice forced the mate.
In that case what is covering the square from which the king took? If anything then the position was illegal on the previous move, because the king was already in check, if nothing then it's not mate.
FBloggs wrote:
What if I sacrifice my queen, forcing the opposing king to take it on the corner square and then I mate next move with one of my two knights? That's a forced mate but it's not forced by the king and two knights. The queen sacrifice forced the mate.
Quite a good question, but MARattigan is correct. We will look at whether the moves leading up to the position are legal under the rules of chess.
Suppose you are planning to mate on h8 and you have a h6 White king. Suppose you intend to sacrifice a queen on h8 while the Black king is on h7. To land a mate, g8 must be attacked before h8 is attacked, so that the Black king cannot escape through g8.
However, this means that the e7 knight (or at least something attacking the g8 square) in my diagram must have been there for a while already, since the final moves to be played are Qh8+ Kxh8 Nf6#, with the Black king having been on g8 before capturing the queen on h8.
This means that, in the preceding turn to the move Qh8+, the Black king must have moved from somewhere (maybe f8 for example) to the already protected g8 square, and of course moving the Black king into an already attacked square would get the Black king captured (or in other words, moving into an attacked square is illegal by the rules of chess) instead of having to go through the queen sacrifice.
Otherwise, if there is no e7 knight guarding the g8 square, Kg8 Qh8+ Kxh8 can be played legally, but the follow up Nf7+ is of course not mate.
Oct 5, 2017
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#136
Optimissed wrote:
<<<<<<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.>>>>>
The fact that chess laws alter occasionally shows that they aren't set in stone. I think this is one illogical and incorrect law or interpretation that will in time be altered.
I would guess you're talking about KNNK rather than the topic of the article, but either way it's extremely easy to come up with a legal sequence of moves to mate (unless the position is already stalemate).
I would say it was preferable to change the Chess.com rules to fall in with the FIDE laws. Would the Chess.com rules declare a draw in the position below?
White to play
Oct 5, 2017
0
#137
goommba88 wrote:
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
Straight up wrong. The longest mate with best play is 33 moves, and that's with the worst position possible.
Optimissed wrote:
<<<<<<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.>>>>>
The fact that chess laws alter occasionally shows that they aren't set in stone. I think this is one illogical and incorrect law or interpretation that will in time be altered.
At the moment FIDE is in support of 'all possibilities' in these checkmates for a win on time ruling, rather than 'reasonable possibilities'. Perhaps this rule may change in the future, but I cannot predict the exact year.
Estrinian wrote:
In 40 years of competitive chess I have never had to play this ending.
Now that I think of it, I have not encountered one such game yet (or at most one or two but I would probably have forgotten already). If I had king and two pawns only, I would probably not take chances with promoting to a knight and a bishop.
Oct 6, 2017
0
#140
MARattigan wrote:
Optimissed wrote:
<<<<<<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.>>>>>
The fact that chess laws alter occasionally shows that they aren't set in stone. I think this is one illogical and incorrect law or interpretation that will in time be altered.
I would guess you're talking about KNNK rather than the topic of the article, but either way it's extremely easy to come up with a legal sequence of moves to mate (unless the position is already stalemate).
I would say it was preferable to change the Chess.com rules to fall in with the FIDE laws. Would the Chess.com rules declare a draw in the position below?
White to play
Yes, it would be a draw here if either player flagged.
If 9. Kg8 then 9... Kh6 10.Kf8 Ne5 11. Ke7 Kg7 12. Kd6 Nd3
No 10. Kh7.
MARattigan wrote: No 10. Kh7 The king cannot go h7 as the black king is on h6.
Apologies. I should have read what you wrote rather than what I thought you wrote.
The point is, if you want Delétang's starting position then instead of 8...Bb3 you should play:
8...Ne5 9.Ke7 Bb3 10.Kd6 Nd3 11.Ke7 Kg7 this is quicker. But quicker still is 8...Ne5(d6) 9.(whatever) Nc4.