Author: Amir Ban
Date: 13:41:30 01/18/98
I did some work on the ECM suite (please don't call it CCC, the original text still deserves credit for it). I looked at the first 100. These are somewhat easier than the rest. In under 20 seconds, I get 81 correct. I am assuming (without good reason I admit) that since I solved them these are correct, and I looked at the other 19. I ran them for some more time, about a minute or so, and also visually analyzed them to see if I can see what the problem is with them. Here is what I find. Feel free to go over my analysis, and point out errors: No. 11 (Nxg4): Junior immediately grabs Bb5 and sticks with it. I analyzed Nxg4 and there is certainly some point to it. These are two completely different plans, and although Bb5 seems better, I'm not sure. Recommend: Add Bb5 as a side solution. No. 14 (Nd5): Junior finds Nb5 immediately. In the deeper analysis, it ultimately prefers Nd5 slightly. Both moves have the same tactical idea. Recommend: No change (but would like to hear other opinions). No. 17 (Rxd5): Junior finds Nf6+. After a long think, it prefers Rxd5 slightly. Recommend: No change, or add Nf6+ as side solution. No. 19 (Rxf6+): Rxf6+ simplifies nicely into a won endgame. However Junior never considers it and find Nxe6 is really crushing. Recommend: Change key to Nxe6. No. 28 (Rxf4): A difficult problem, and somewhat vague. I am not close to finding it, but by following the sequence Rxf4 Bxf4 Nxf6+ gxf6 Qg4+ Bg5 Bxg5 f5 it looks like it does work in the sense that it's better than the alternatives, but I cannot see a plus score. Recommend: No change, or else drop it for reason of vagueness. No. 29 (Rgxg6): A classical problem which is found easily. The idea is that after the knight on g6 is gone, Qe5 wins. However, after a few seconds Junior prefers an intermediate Rxa6 Qxa6 Rxg6 which is the same plan but more effective. Recommend: Add Rxa6 as side solution. The problem is that playing Rxa6 doesn't prove that your program understood this position. No. 43 (Bxg2+): Junior takes Qxc2 fast and sticks with it, thinking that white is forced to give up the exchange with Rxg4. Looks like this works, and is somewhat better than the key. Recommend: Add Qxc2 as side solution. No. 51 (Rxh2): Was not solved in 20 seconds, but turned out in the deeper think, but with an unconvincing score. I didn't analyze it. Recommend: No change (but someone else should look at it). No. 60 (Bxh2+): This one looks wrong. Junior has Qh6 which seems winning (Nf3 Nd2!). Looks much more convincing than Bxh2+, where I don't see a win. Recommend: Change solution to Qh6. No. 63 (Ncxd5): Junior has Nbxd5, and this looks like a simple transpostion. Recommend: Add Nbxd5 as side solution. No. 68 (Bd3): I don't understand the key move. Bd3 Qxc3 Rg4 Qxa1 Bxa1 Nxg4 Qxg4 g6 looks like just a creative way to lose material. I don't see anything else here. Recommend: Drop this problem. No. 71 (Qh6): Qh6 leads to material gain, and Junior finds it quickly, but after a few seconds insists on the quiet and subtle Kg2! Black loses a rook at least. Recommend: Change solution to Kg2. No. 76 (fxg6): Junior switches to fxe6 and sticks with it. Analyzing both options, the key is correct but fxe6 is at least as good. Recommend: Add fxe6 as side solution. No. 78 (Nxc5): Was not found in 20 seconds, but turns up convincingly later. Recommend: No change. No. 81 (Qb1+): Junior takes Bxc6, with idea Bxc6 Qd8 Qb1+. The idea of the key Qb1+ is that the white queen is lost on a8 because of mate threats. Junior's side solution uses the same idea, showing that the queen is equally lost on d8 ! A nice cook. Recommend: Add Bxc6 as side solution. No. 82 (exf6): Not found in 20 seconds, but turns up later. Recommend: No change. No. 84 (Bg6): Junior plays the unspectacular cxb5. The key Bg6 looks sound, but it only forces the exchange of heavy pieces and leads to an endgame with advantage. Recommend: No change, or drop it on grounds of vagueness. No. 91 (Nc6): Junior switches between Nc6 and Nxe6. It finally adopts Nc6, but Nxe6 may not be far behind. Recommend: No change. No. 96 (Qe8+): This one's correct and is mate in 5, but so is Nf6+ with a different move order. Recommend: Add Nf6+ as side solution. Amir
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