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        riddles >> medium >> White to Play and Win
        
(Message started by: THUDandBLUNDER on Dec 31^st, 2003, 12:14am)

Title: White to Play and Win
Post by THUDandBLUNDER on Dec 31^st, 2003, 12:14am

This is a standard type chess puzzle.

Title: Re: White to Play and Win
Post by Dudidu on Dec 31^st, 2003, 1:20am

I would say:[hide] the white player first move sholud be bF1 - if the black king "takes" it (now or as long as the game continues)then the white pawn can reach H8 safely (and thats a winning position), o/w the second white player's move will be h3 (and thus the white pawn is defended by the white bishop) which will "gain" the the white king "enough time" to "reach the area", a thing that can force a white win...[/hide].
I hope my description is understandable.

Title: Re: White to Play and Win
Post by THUDandBLUNDER on Dec 31^st, 2003, 1:41am

Quote:

which will "gain" the white king "enough time" to "reach the area", a thing that can force a white win....

If White plays 1. Bf1 Black replies Kc3 and reaches 'the area' (the queening square) first.
Furthermore, it cannot be evicted by the white-squared bishop.

Title: Re: White to Play and Win
Post by Margit on Dec 31^st, 2003, 1:46am

I think the key is to stop black playing F3. Therefore
I play [HIDE]B-G4, followed by H2-H4[/HIDE]
That looks as if it should work.

Title: Re: White to Play and Win
Post by Dudidu on Dec 31^st, 2003, 2:24am

on 12/31/03 at 01:41:15, THUDandBLUNDER wrote:

and reaches 'the area' (the queening square) first...

Same problem as in White to Play and Win II - double oops... :-/ :-/

Quote:

That looks as if it should work...

It doesn't seem like this help...[hide]
1. B-G4 K-E3
2. H2-H4 K-F4
and still the black king is reaches 'the area' faster...[/hide]::

Title: Re: White to Play and Win
Post by THUDandBLUNDER on Dec 31^st, 2003, 2:46am

on 12/31/03 at 01:46:27, Margit wrote:

I think the key is to stop black playing F3. Therefore
I play [HIDE]B-G4, followed by H2-H4[/HIDE]
That looks as if it should work.

It doesn't.

1. Bg4 Ke3
2. h4 Kf4
3. B moves Ke5 (if 3. Bh5 Kg3)

Title: Re: White to Play and Win
Post by Margit on Dec 31^st, 2003, 2:47am

Sure it does. After the bishop move, what can black do ?
He can't move F3 or G3 (check) and any one of G1, F1, E1, E2 or E3 loses immediately. Therefore he moves [HIDE]G2 but after H2-H4, he is always one move behind (try it).
G3, H5, G4 (the bishop is now irrelevant), H6, G5, H7, G6, H8[/HIDE]

Title: Re: White to Play and Win
Post by Margit on Dec 31^st, 2003, 2:53am

Whoops, Looks like E3 and then up the C1-H6 line stops this.

Title: Re: White to Play and Win
Post by Margit on Dec 31^st, 2003, 3:04am

Ah, I think I have an idea.
We move [HIDE]B-C8 and follow it with H2-H3.
Then we have all the time in the world to move the king over to the G file. Haven't played it out yet, but it may work.[/HIDE]

Title: Re: White to Play and Win
Post by Dudidu on Dec 31^st, 2003, 3:24am

on 12/31/03 at 03:04:47, Margit wrote:

Ah, I think I have an idea...
we have all the time in the world to move the king over to the G file.

Margit, it doesn't seem to work. The reason is similar to the reason that T&B gave as a response for my initial answer...

Title: Re: White to Play and Win
Post by Margit on Dec 31^st, 2003, 4:02am

Actually, I think I like [HIDE]G4 then H3 better[/HIDE]
Then I am fairly sure we can get the white king onto the F,G,H files.

Title: Re: White to Play and Win
Post by THUDandBLUNDER on Dec 31^st, 2003, 4:11am

Did you know that positions with KB + KRP + K v. K are drawn (provided the lone king can control the queening square, h8)? However, this is a rare exception.

Title: Re: White to Play and Win
Post by Margit on Dec 31^st, 2003, 4:18am

No, TB, I didn't. I sort of had this in the back of my mind when I saw that black could just ping-pong between G7 and H8. Hmm

Title: Re: White to Play and Win
Post by James Fingas on Dec 31^st, 2003, 5:24am

The bishop evidently must make the first move, since the pawn can't move and if the king moves first, the black king will play g1 and steal the pawn.

I'm thinking that B-d7 might be good. Note that the black king must make straight for h8 as long as white keeps moving the pawn. So here's how it would go:

[hide]1. B-d7 K-e3
2. h4 K-e4
3. h5 K-e5
4. h6 K-f6
5. B-e8 ??

So the black king can't go straight into the corner, and has to take a step back, either to d7 or g5. Either way, he can't get to the corner in time.

If black tries to short-circuit this approach by

2. h4 K-f4

then white plays

3. K-d4

and cuts him off. Black must then backtrack to either f3 or g3. Either way, he can no longer catch up with the pawn.

w00t! My first chess puzzle![/hide]

Title: Re: White to Play and Win
Post by THUDandBLUNDER on Dec 31^st, 2003, 9:14am

Yes, that's right, James.

In fact, the original position is mate in 15 moves against best play.