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Kevin Bonham
27-09-2007, 01:09 AM
Have you ever had the majority in a BBK v. K ending?
Those that vote yes are invited to say how many times in how many years (or games) of competitive chess.

[This may look suspiciously similar to another endgame poll going around at the moment. Just curious, will comment later.]

Garvinator
27-09-2007, 01:22 AM
Have not even been on the minority side of this ending.

Rincewind
27-09-2007, 09:46 AM
Not in my database of competition games (over the last 7 years, approximately 350 games). The closest is I have been 2B up with pawns on both sides but only momentarily and my opponents next move was PxB. :)

Capablanca-Fan
27-09-2007, 11:18 AM
I have in offhand games but not in a tourney AFAIK. Maybe lightning tourneys.

Southpaw Jim
27-09-2007, 01:29 PM
Zero, although with my limited (~50 OTB rated games) experience, that's hardly surprising..

Kevin Bonham
27-09-2007, 03:01 PM
I have never had it in a tournament game of any kind although I have had it in a casual game 15+ years ago (and won). Casual games don't count so I've excluded that in voting.

The reason I started this poll is that in the Complete Endgame Course thread, Eurotrash notes:


Silman feels that K+B+B achieves this end, and that it's more likely to occur OTB.

But I wonder if Silman is actually correct about this. As a simple matter of probability KNB vs K, all other things being equal, should be as common as KBB and KNN vs K put together (just as, for instance, if you toss two coins, HT occurs half the time and HH and TT a quarter of the time each, because there are two different ways you can get HT).

Obviously there are many reasons why not all other things might be equal. For instance, it may be that KBB vs K is a common outcome of a minor piece ending in which the side with the two bishops uses them to gain a pawn, then force the opposing side to sacrifice a piece to stop one pawn, then force the opposing side to sacrifice the other piece to eliminate another pawn (etc).

In weak junior chess I see KBB and KBN about equally often, and both significantly more often than KNN. But this may just reflect that weak juniors handle bishops better than knights.

At club or tournament level I have been on the defending side of KBN, and have seen KBN a few times, but cannot remember the last time I saw KBB v K - though it may be it arises rarely because players go into other losing endings to avoid it, or resign when they see it coming.

Capablanca-Fan
27-09-2007, 03:15 PM
At club or tournament level I have been on the defending side of KBN, and have seen KBN a few times, but cannot remember the last time I saw KBB v K - though it may be it arises rarely because players go into other losing endings to avoid it, or resign when they see it coming.
That's probably a factor. While the defender has a sporting chance against most people with KBN, he would realize that he has slim to zero chance against KBB held by a half-way decent club player. It is just too straightforward to use the Bs on adjacent diagonals to confine the K, while it takes some training to use the BN together.

Bereaved
27-09-2007, 03:32 PM
Hello, Everyone

I do know of a game played at MCC some years ago, when in the adjourned position, one player had two bishops vs a knight and a pawn. After resumption of play, the pawn was rounded up first, and then the knight. There was not a resignation at this point, but there was a loss on time in a position akin to:

W: K b8; B: K b6, Be5, Be6;

and the said loss of time occurred after the player with the lone king sat there for his remaining 40+ minutes until he lost on time.

In any case, I do not recall someone playing on to reach such a position before, although have had numerous persons play on in hopeless, material down position before.

Take care and God Bless, Macavity

PS the technique of winning with 2 bishops v knight is described in Secrets of minor piece endings by Nunn ( Batsford )

Southpaw Jim
27-09-2007, 03:33 PM
The reason I started this poll is that in the Complete Endgame Course thread, Eurotrash notes:

I suspected this was the motivation, and I must caveat that I was going from my memory. I'll check tonight when I get home whether, in fact, this was Silman's reasoning. I could've been misquoting him, and he may've justified it on the grounds that KBB is easier to learn or something else entirely - stay tuned.

Aaron Guthrie
27-09-2007, 03:42 PM
I suspected this was the motivation, and I must caveat that I was going from my memory. I'll check tonight when I get home whether, in fact, this was Silman's reasoning. I could've been misquoting him, and he may've justified it on the grounds that KBB is easier to learn or something else entirely - stay tuned.The difficulty involved in learning it was at least partially the reason, see http://chesschat.org/showpost.php?p=168867&postcount=22

Basil
27-09-2007, 06:43 PM
Damn. I was hoping to nip this in the bud when I logged on this morning (before I had to go down to the coast and buy another car - true story - don't tell fg - he'll burst a blood vessel).

Last night I came across page 188 odd in the book and read an elaboration of Silman's previous (quoted) text.

Sounds like Euro will get there before me, but Silman talks about BBK being just as unlikely as BNK, but he gives a rationale for his decision.

Southpaw Jim
27-09-2007, 07:05 PM
From p.188:


In general, every position I give in this book will happen fairly often, or understanding it will allow you to solve other positions with similar themes. I don't feel Bishop and Knight vs King falls into this category, but then, two Bishops vs King is also a rare bird in tournament play. So why should I insist you learn two Bishops vs lone King? There are three reasons for its inclusion:

- I find the need to use all three of your pieces in a balanced team effort to be quite instructive;
- Seeing how powerful two Bishops are when working together can be enlightening;
- It's very easy to learn and only involves a small expenditure of time to fully understand.

Thus, I apologise for misleading people! :uhoh: :wall:

likesforests
29-09-2007, 12:33 PM
I faced the situation once in my last 120 games, with pawns:
FEN: 8/1bk3p1/4p3/pp2P1b1/2p1p3/P1P1P3/1P3K1P/8 b - - 0 34

That's disappointing, if you consider how many hours I spent mastering K & 2Bs vs K & 4 Ps:
http://likesforests.blogspot.com/2007/08/two-bishops-mate.html

At least I've come to appreciate the bishop pair much more in my own games.