15 March 2011

More Blogs @ Chess.com

While working on the post about Blogs @ Chess.com, I ran into a couple of ideas worth recording.

Is This Position Legal?

The first was a series on legal positions by blog.chess.com/CuzinVinny. Vinny's first two posts were:-

His right sidebar currently shows two more positions. This looks like a good idea for players who are just learning the rules of chess, but might also be challenging for more experienced players. Another puzzle in the same direction is from blog.chess.com/DandyDanD:-

I haven't yet figured out the 'extra credit' in that last post.


Another post, which has since been deleted (a frequent, annoying occurrence at Chess.com blogs), asked,

Does anybody know, can you promote a pawn to a bishop if you still have that SAME COLOR BISHOP on the board?

This is a typical beginner's question, but it got me wondering if underpromotion to a second Bishop of the same color had ever been the only way to win/draw a game or a study. I couldn't find an example, but I did learn a few other things. First, it appears that chess engines don't often consider underpromotion.

Rybka does accept Bishop underpromotions. She just won't suggest them as best moves. • Bishop Underpromotion [Rybkaforum.net]

Then I found a cute anecdote on the theme.

I remember an incident from when I was a teenager involving Bishop underpromotion. An expert and an "A" player were paired in a local tournament. In this particular game the expert was frustrated as he had an extra Bishop and his opponent was still playing on. Expert simplified down to a position where he had a King, Bishop, and Pawn versus a lone King...and STILL the A player wouldn't resign! Expert nursed the pawn to the 7th rank, and in a gesture of contempt...underpromoted to a Bishop. Only AFTER slamming the newly born Bishop down on the last rank and hitting his clock did he realize...IT WAS ON THE SAME COLOR AS THE OTHER ONE. • Thread: Underpromotion [chesscircle.net, post by dancingbear]

It also adds another argument to the never ending discussion of why some people never resign. Finally, I found a long essay by Tim Krabbé that started,

In 1912, in The Theory of Pawn Promotion, Alain White wrote that he had 'never heard of a game where victory was won by a promotion to Rook or Bishop'. In 1936 the great endgame connoisseur Harold Lommer wrote something to that effect too. In my own Chess Curiosities (1985) I mentioned the 'extreme rareness of such promotions', and quoted 12 examples from all of chess history, including trivial ones. Ten years later Harold van der Heijden, in his Pawn Promotion, extended the list to 27. We had entered the database era - he had used a 400,000 game one. Over the following two years, in the magazine EBUR, he showed some 15 new cases. My turn again - in the meantime the databases have grown to almost 2,000,000 games, and if I used the same criteria as in 1985, I could show over 60 examples now. • Practical Underpromotion [xs4all.nl/~timkr]

Considering the rarity of legitimate Bishop underpromotions of any kind, it seems unlikely that an example exists for a second Bishop of the same color.

No comments: