The Chess Mind

I recently came across an old Karpov-Kasparov game from 1991, and it featured a material imbalance I'd never seen before in an endgame: two knights and a bishop against a rook, with no pawns for either side. Kasparov drew with the rook, but I wonder what's supposed to happen with best play. Here are my preliminary thoughts on the topic:

1. Because two knights vs. a king is a draw, White always has to watch for RxB sacs.

2. By analogy with B+N vs. K, the minor pieces will probably have more success generating mating threats if the weaker side's king is forced into a corner of the same color as the strong side's bishop.

3. The fact that Karpov didn't succeed in winning at a time when - I think - adjournments were still in place strongly suggests that the ending is (generally) drawn. There's no tablebase data on this ending, however (or if there is, it's brand new and not in my possession), so I don't know for sure.

John Nunn has a book treating pawnless endings - if any of you has that and could look up this ending and pass along the findings (if any), that would be great. (Likewise if anyone has genuine knowledge about this ending from some other source.)

Thanks, readers, and you can replay the game here.

A couple of days ago, I offered my readers a problem even Hydra won't solve - at least not all at once! Here's the starting position:



For the solution in all its 257 move glory, see here.

My recent posts on "doing nothing" (here and here) have reminded me of the genre of chess studies called "monsters" - problems whose solutions are extremely long, generally because they require multiple iterations of a certain sequence to occur before the win can be executed.

I first learned about these problems from Soltis's Chess to Enjoy (the book, not his monthly Chess Life column), in which he brought to the attention of a larger audience the king of the monsters, Oscar Blathy.

Here's the longest-lasting of his puzzles, as far as I can tell: White to mate in 257 moves. Good luck, and feel free to use your chess engines.



The solution will be given in a couple of days, which may have been how long it took Blathy to write all the moves down when he created this back in 1890.

The study was initially presented here, while the solution be replayed here. It's a nice puzzle in its own right, but its particular interest at the moment comes from my software's inability to solve it. The computer's problem is that although it doesn't take too many plies to reach the positional drawn, "understanding" that's what it is takes many more plies, due, as you'll see when you've solved it or replayed the solution, to the fact that Black can drag out the inevitable.

This event, taking place in Paks, Hungary, is a double-round robin featuring the following participants:

Emil Sutovsky (2665, Israel, 27 years old)
Krishnan Sasikiran (2642, India, 24)
Zoltan Almasi (2628, Hungary, 28)
Viktor Korchnoi (2619, Switzerland, 74)
Ferenc Berkes (2617, Hungary, 19)
Peter Acs (2525, Hungary, 24)

One might expect that one of the higher-rated players was in the lead, or perhaps one of the Hungarians, enjoying home-field advantage. Nope.

The leader is the inimitable one: the 74-year old Viktor Korchnoi!

Korchnoi 4/5
Almasi 3.5/5
Sutovsky 2.5/5
Sasikiran 2/5
Acs, Berkes 1.5/5

Click here to replay his fourth-round win over top seed Emil Sutovsky, and note especially his nice 48th move, which sped up the technical task considerably.

On Monday, I presented a pair of challenging endings for your instructional and solving pleasure, and promised the solutions in a "couple" of days. Mea culpa! Hopefully, that just gave the intrepid souls in my readership a bit more time to work things out; in any case, you can play through the solutions here, once you're ready.

Some draws are dull, but not all of them - this one had even the IMs and GMs in the internet audience oohing and aahing!

Click here.

I'm generally pleased as punch to point out what computers can do, but it's also nice to see sometimes what they can't - at least not yet. Along those lines, here's a neat study shown to me today by "BraafPaard" which neither his ChessMaster 10000 nor my Shredder 9 were able to solve.

I was in a bit of a rush to solve it, so rather than try it on my own I did a tandem job with the computer and figured it out pretty quickly, in good part because I knew what to look for. Give it a try and see how you (and your computer, preferably after you're done flying solo) manage to do with it.

Also, if anyone knows the author of this study, please drop me a comment or an email to let me know, so he or she can receive proper credit.



White to move and draw.

It's well-known that a bishop and a rook pawn is insufficient to win against a bare king (assuming the king can reach the queening square) when the bishop is of the opposite color of the queening square. Here's a basic example:



White can huff and puff and stalemate Black, but nothing more. The concept is very simple, but the wonder of chess is that from even such simple materials positions of immense complexity can be constructed. Here are two for your solving pleasure - remember to keep the chess engines switched off, and if you haven't solved them by then, don't despair: I'll present the solutions in a couple of days.





White to move and win in both cases.