Wednesday, July 25, 2007


I feel like I've seen this post from other bloggers. My hard drive crashed. At the moment it doesn't look like I'll recover any data from it. Everything really important was stored elsewhere, but this does not include CT-Art stats.

As of the crash, I had about 16 problems to go before completing the 1209 problems. What a heart breaker. My percentage on the level 90 and above problems was 69% and my CT-Art elo was 2610. At this point I consider myself having gone through the problem set once. My computer is up and running with a new hard drive. I'll probably re-install CT-Art and do the problems over -- hopefully better.


Thursday, July 19, 2007

CT-Art coming apart at the seams

Ok, I'll say it. The makers of CT-Art did not put in the necessary effort to make problems at the highest difficulty they intended. They have flat out failed to make the problems on the last level correct. I'm not just blowing gas here either, I'll give you two very concrete examples -- and I promise the last levels are riddled with this kind of thing.

First, a simple example. A position from problem 1178.
White to move

White has crashed through on the kingside and just needs to polish off the mate. The first thing that came to mind was f7. This threatens mate on g8 and forces Bg7 (other bishop moves allow Qxh6). Then white will play Ne4 planning Nf6 or Ng5 threatening Qh7 or getting the queen to the h-file (e.g. Nf6 Bxf6 Qxh6 or Ng5 hxg5 Qh5).

With those ideas, we think, what if white plays Ne4 first. Black does not seem to have any real productive moves. Certainly not any more productive than he would play after Ne4 in the previous line. If you're really keen you'll realize that the move order with Ne4 first leaves the f7 square open for the knight, e.g. Ne4 c5 Ng5 threatening Nf7 (if hxg5 Qh5 leads to mate quickly).

The CT-Art solution was f7, with no credit for Ne4. The best line for black after f7 is Bg7 Ne4 c5 (CT-Art gave Rd5 falling for mate in 2) Nf6 (or Ng5) Be4 Nxe4 (Notice f7 is unavailable for the knight!) e5. White is ahead 2 pawns and has a much safer king, but the move order with Ne4 first was clearly better.

Ok, that was the simple example. At least the solution given by CT-Art was actually winning. Problem 1177 was riddled with even worse errors. This takes some time to explain the multitude of errors, feel free to skip to the end of the rant.
Black to move
The first move, Bxh3, is difficult to calculate all the consequences of, but it's easy to see the white king position will be exposed and there will be chances for black. White's response gxh3 is forced. Now CT-Art completely misses the win. Qxh3 threatening Nf3 mate. Be2 is forced. Black then has Nd5 and after white moves the queen away, Qa3 Ng4 Bxg4 Qxg4+ Kh1 is forced.Black continues, Nxe3 fxe3 (forced) Qh3+ Kg1 Qg3+ Kh1 Rd5 Threatening mate.

White has to block the rook from going to h5 using either the knight or rook on f5. This gives a piece back to black after Rf5 Rxf5 Nxf5 Qh3+ Kg1 Qxf5. This leaves black ahead to pawns and the white king remains exposed.

This line starting with Qxh3 is not the solution given. Instead, the program gives what is actually a move that does not lead to an advantage. After Bxh3 gxh3 from the starting position, CT-Art gives Rxd4 Bxd4 Nf3+ Kg2 Nf5.

Position A, White to move

And now a poor move is played by white to allow black to win. CT-Art doesn't even consider Rfd1 which allows white all the wiggle room he needs to stay alive. The program gives Be3 as the main line. This allows N5h4 Kh1 Qf5 and the threat of Qxh3 is too strong.

The program also gives two other lines from 'Position A'. First, Bf6 gxf6 Rh1

And now the baffling Re8. There is no commentary or further moves after Re8 except that they give it an '!'.

The second line from 'Position A' is Rg1 N5xd4 Bd3 (another questionable move from white) Nxg1 (Qe5 was much better) Qxd4 Nxh3 Rh1 Qd5+ Qxd5 Nf4+ Kf3 Nxd5. After all that, black has a two pawn advantage.

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Thursday, July 12, 2007

Random positions

Not a whole lot to say lately. Just plugging along. Here are some positions from recent games:
White to play

This is from a blitz game. Here white is losing the b-pawn, so I decided to go for a swindle. Here were the next moves: g4 Nxb3 g5 and black falls for it, hxg5??

White to play

Now white has a winning tactic. Rf3 threatening mate on h3 and the knight on b3. Phew, I got away with one there!

Here is an example of an un-developed queenside. White has made a bunch of queen moves and has now tried to lock the center with d5:

Black to play

But it turns out the rook on e1 is overworked. Black can break through with Nxe4. White didn't put up the toughest resistance. The game continued Rxe4 Qxc1 Kh2 Qxd2 Nbxd2 etc.

Lastly, an example of breaking open the center. Opening the center is generally better for the better developed side. That's a good rule of thumb for getting ideas, but you also have to calculate quite a bit because a lot of lines will be open.

White to play

White is a little more developed due to the rook on d1. More importantly, white's pieces are actually aimed at targets. The e3 bishop attacks the b6 knight and the d2 queen is lined up on d7 bishop while both of these pieces are defended by the queen. Also important is that the d1 rook is lined up on the queen.

So white opens it up with d5 exd5 Bxb6, the game continued with Qxb6. A better try, but still good for white would have been axb6 exd5 Be8 Qxc4. The game move loses quickly exd5 and now both bishops are under attack.

Lastly, an update on CT-Art progress. The last level is problems with difficulty 90 and above:
Level 90 and above: 74%, 22 problems done, 45 to go.
Ct-Art elo: 2587
1164 problems done, 45 left. Then, who knows, back to the beginning??

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Wednesday, July 04, 2007

Level 80 Done

Happy Independence Day to my fellow USAers.

I've finished Level 80 of CT-Art. No other great insight at the moment, just the facts:

CT-Art stats:
Level 10  20  30  40  50  60  70  80
# 110 286 221 204 134 84 59 44
% 97% 92% 86% 77% 76% 67% 70% 64%
CT-Art elo: 2522
So I've completed a total of 1142 CT-Art problems. There are 67 problems at Level 90 and above.