Bishop, Knight & King versus King.

MARattigan

It is more difficult to do it in the shortest number of moves against accurate defence, but even that would be easy if you knew how.

MARattigan
GoodKnight0BadBishop wrote:

The American Flag is what is next to my username.

Oh.

RubenHogenhout
GoodKnight0BadBishop schreef:
MARattigan wrote:
GoodKnight0BadBishop wrote:
xman720 wrote:

1: Can you show how that works in the relevant position instead of an easy position.

2: I'm pretty sure if black hadn't run straight towards h1 it would've taken a lot longer to mate him.

You give me a position and I can checkmate from there.

After after Black's obvious 6...Ke5 in your example, can you still do it in 19?

 

I'll offer to play Black against you in this one if you like.

Black to move.

 

Whoa! If it is black to move in that position, then he'll play Kf3 followed by the unstoppable Kg2 trapping the knight! Those positions are exceptional positions where a piece is lost. Give another position.

 

Right with black on move the knight is lost. With White on move you can win like this.

 

 

MARattigan

One move quicker is:



 

MARattigan
drbob_mccord wrote:

 I got it once in a practice game but that was only once in many attempts. It only takes one slip in the worst case 30 move position to give away a half point. Still there is a technique, but I wouldn't steer into this ending in an over the board game and expect to win. If you have a chess computer it wins infallably and Paul Keres explains how to do it well in his book "practical chess endings" but you can't take the book into a tournament or use a chess computer!

I bought Keres' book once, though it opted not to get off the train at the same stop as me a few days later.

I was put off Keres' explanation by the fact that he blundered with Black on move 2 and then failed to take advantage on move 3 with White.

Curiously I had occasion to get Batsford Chess endings recently and noticed they do exactly the same, and as far as I can remember (it was about 45 years ago I bought Keres) from the same starting position. (Not accusing anyone of copying you understand.)

This is not a small blunder. I tried playing the Nalimov EGTB  from the position after move 2 in BCE and finished in half the time the text takes. I think Keres might even have taken one move longer than BCE.

drbob_mccord

My Keres book has long gone too, but someone on this site explained it much better than Keres and now having looked at this forum I wouldn't be scared of encountering the ending!

MARattigan

@playerafar: In response to your post #118:

 

There is nothing wrong with your memory, but there is something wrong with my text editing. It was actually a post by Squod that stated the 10x10 idea and I copied too much of the post.

 

You ask if the mate is possible on a 10x10 board if the king is in the centre. I think the answer is not necessarily, (This is why I said the position I gave would be drawn if the king positions were interchanged. In that case I think the black king could reach a position in the centre where White could not avoid a draw by repetition - or 50/75 move rule if taken into account). But to allow a mate by White, the Black king need be neither at the edge nor close to the "right" corner. E.g.

 

null

White wins if the Black king is in the coloured area (White to play)

or red area (either side to play).

 (The area shown for the Black king above is by no means  exhaustive.)

 

When I said I would guess that mate would be possible within the 50 move rule on a 10x10 board I was, of course, referring only to positions where mate would be possible in the first place. Even so after looking at it a bit closer I would now say I guessed wrong and the longest mate would probably be nearer 60 moves than 50.

 

I will answer the remainder of you post shortly. This ties in with xman720's query on how to avoid ceding moves at the start of the endgame so I will make it a joint answer.  But the answer will necessarily be a little more comprehensive, so it will have to wait till I've moved house. 

playerafar

Lol! - had to delete this comment - as it was WRONG -
unfortunately - this forum doesn't accommodate a complete delete.
Which much of V3 does.

eric0022

Interesting post on a 10x10 board by MARattigan on post #147.

drbob_mccord

Hard enough to force the mate on an 8x8 board never mind 10x10😀

playerafar
drbob_mccord wrote:

Hard enough to force the mate on an 8x8 board never mind 10x10😀

I guess the idea might be -
that how this works on a 10x10 might help with understanding the 8x8.
That doesn't mean it works out that way though.

The N+ B versus lone King endgame is one of the irksome little gremlins of chess.
And there are so many of them.
Its almost like - its about how much time one has to deal with it all.
And even if ALL of one's time is spare time - its not going to be enough time ... happy.png

Dioscuros

ok

drbob_mccord

Yes I see the point if it is illustrating an idea. I suppose they might change the 50 move rule for a 10x10 board and apart from 4 extra pawns you would have to have an extra piece to sit outside the rooks. A whole new game!

playerafar

In Chinese chess - there's a "river" in the middle.
And if I remember correctly - once you've crossed it - you can't go back.
An interesting game.  
Maybe a thread could be started on it.

Interesting point.
Threads can be started - without being part of a Club.
In a way - each one of same - is a kind of Club.
And the original poster - is the admin.

I never was aware of any of this before - because I didn't use forums and threads and topics.
I was only in chatrooms ...

prusswan

There are two main parts: pushing to the side then pushing to the corner. Both are easily mastered with practice.

playerafar

But you have to let the King off the side.
I believe that that idea of forcing the King to the side of the board - misleads players.
And creates needless difficulty.

Much much better is Deletang's Triangles.
You confine the King to a triangular zone.
Fits very well with how a bishop moves.
Pushing to the side would make more sense with a rook.   But you haven't got a rook.
As for getting the target King out of the center - that's super-easy.

You just bring your King to the center.  You've got two extra pieces to move.
You can get him out of there - using zugzwang - and controlling squares next to him.
So he retreats from the center.  Its not necessary to force him to the edge.
He's coming off the edge anyway.

Taurus44

Its tricky, but of course possible.

I studied this combination for a week happy.png

The most difficult endgame is queen/king versus rook/king

prusswan
playerafar wrote:

But you have to let the King off the side.
I believe that that idea of forcing the King to the side of the board - misleads players.
And creates needless difficulty.

Much much better is Deletang's Triangles.
You confine the King to a triangular zone.
Fits very well with how a bishop moves.
Pushing to the side would make more sense with a rook.   But you haven't got a rook.
As for getting the target King out of the center - that's super-easy.

You just bring your King to the center.  You've got two extra pieces to move.
You can get him out of there - using zugzwang - and controlling squares next to him.
So he retreats from the center.  Its not necessary to force him to the edge.
He's coming off the edge anyway.

There are two approaches for Part 1 (getting to the side) which may be the source of confusion, but general ideas are the same: use the bishop to gain/lose tempo, and the knight to cover the squares the bishop cannot. I don't use the triangles approach which requires more memory.

playerafar

Forcing the King to the side is part of the confusion - even though that part is easy.
You have to let him off the side anyway.
That's where it gets tough if you're not using the Triangles approach.

As for "more memory" - its my experience that the other approach is harder to remember.
Maybe there's a middle ground between the two.  Haven't looked into that yet.