Dennis M's Chess Site

This is a blog for chess fans by a chess fan. I enjoy winning as much as anyone else, and I've had a reasonable amount of success as a competitor, but what keeps me coming back to the game is its beauty. And that, primarily, is what this site will be about! All material copyrighted.

Tuesday, February 08, 2005

What Computers (Allegedly) Can't Do

Our parents and grandparents used to say, when faced with some oft-repeated hyperbole, that if they had a nickel for every time someone said such-and-such, they'd be millionaires. Perhaps I wouldn't be ready to enter the 7-figure bracket, but I feel that same sense of ironic exasperation when I read that computers will never find this idea or that. Nowadays, my practice is to always put such claims to the test as soon as I have the chance, and almost without exception, the computer proves equal to the challenge.

Enter tonight's interview with Tigran L. Petrosian in the Chess Cafe. Petrosian, a strong young Armenian GM (not the late world champion, nor related to him), presents two of his games, including a win from the recent World Junior Championship. (Two asides: first, he came in second in that event. Second, the game is mistakenly marked "1-0" at the end; it should be 0-1.) Here are the moves leading up to the critical position:

Sengupta-Petrosian, W Jun U 20, Kochin 2004

1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.g3 Nxe4 5.Nxe4 d5 6.Nc3 d4 7.Ne4 f5 8.Neg5 e4 9.Bc4 exf3 10.Bf7+ Kd7 11.Be6+ Ke8 12.Bf7+ Ke7 13.Bb3 Kf6 14.Nf7 Qe8+ 15.Kf1

Petrosian now played 15...d3(!!) and writes this: "Human intuition is stronger than computer calculation! Set this position up on any analytical engine, let it think for hours, and it still will not be able to find this move. Fritz suggests 15...Qe2+ 16.Qe2 [sic] fe+ 17.Ke2 Rg8 18.Nd8 Rh8 19.Nf7 Rg8, with a draw."

The new program Junior 9 is my current default engine, so I let it get started, looked at my computer's clock, and prepared to settle down for a long winter's nap.

One minute passed,

and before I could spring to the window to see what was the clatter, Junior had determined that 15...d3 offered a clear advantage for Black, and didn't change its mind over the more than 20 further minutes I let it run. Okay, perhaps that's just Junior. Petrosian said that one could set the position up on any analytical engine, but Junior has a reputation for being particularly sharp and willing to risk a bit more for the initiative. So just for kicks, I gave the position to Fritz, and sure enough, things were different.

Fritz took 30 seconds.

Now, I don't have a super-computer. I don't even have a multi-processor machine. It's a reasonably new, reasonably powerful machine, but nothing extraordinary. So maybe Petrosian was using an old computer or didn't wait more than a few seconds, but whatever the explanation, this position is well within the power of contemporary engine + hardware tandems.

So readers, don't be afraid to use your computers to test grandmaster claims. Chess software works best when it's guided, and there are still positions that they can't handle particularly well, it's true. But if I had a nickel for every time I heard someone say, wrongly, that computers can't find some move or that they don't understand some position or other, well...


  • At 5:04 PM, Blogger Ken said…

    What positions do computers not handle particularly well? I know about the generic closed positions, but other than these ones, where are they weak? I'm curious because I play correspondence-style chess and some people may use computers to "assist" them. Mostly, I don't mind because I still get to play a good game of chess and that is all I'm really interested in. However, if I suspect someone is repeatedly using a computer program in all the games how would I steer the position into something where I may have an advantage over a program (or at least, more of an advantage)?

    And since this is my first post to your site, I'd like to say "great job" on your Monday night programs.


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