bill@milford.UUCP (bill) (03/26/85)
. About a week ago the 5 MHz Fidelity Challenger which I had ordered from the USCF arrived and I was rather disappointed with its play against me, I felt it was playing rather like a class D player instead of the class A or expert which was indicated. Rather than list its games against me (even though I've always wanted to have my games published) I set it up to run against my old Challenger 9 from several years ago, the results are interesting: (both were set at 40 moves in 2.5 hours) White: 5 MHz Chal 12 Black: 2? MHz Chal 9 1 e4 e5 2 Nc3 Nf6 3 f4 d5 4 fe Ne4 5 Nf3 Be7 6 d4 o-o 7 Bd3 f5 8 (out of book) o-o Nc3 9 bc c5 10 Ba3? (immediately) Qa5 11 Bb2 Nc6 12 Re1? Be6 (immed.) 13 Qd2 Qa4 14 a3 Rae8? 15 Be2 Na5 16 Ld3 Nc4 17 Lc4? Qc4 18 Rac1 Qb5 19 Rb1 Rc8 20 Qf2 Qa4 21 Bc1 Rc7 22 Re2 cd?! 23 Nd4 Lc5 (immed.) 24 Rb3 Bd7 25 e6 Bb5 26 Re1 Bc4 27 Rb1 Ba4? 28 Ra1 Bd4 29 Qd4 Qc2?! 30 Bf4! Rc6 31 Qa7 Rc3 32 Qb7 Qb3 33 Qd7 Qa3 34 Be5 Rc7 35 Qc7 Rf6 36 e7 Qe7 37 Qe7 Rf7 38 Qe6 h7 39 The 5 MHz Challenger announced mate in four. White: Chal 9 Black: 5 MHz Chal 12 1 Nf3 d5 2 c4 d4 3 g3 (out of book)Nc6? 4 Bg2 e5 5 d3 Nf6 6 o-o Bd6 7 Bg5 o-o 8 Nbd2 h6 9 Bf6 Qf6 10 Ne4 Qe7 11 Rc1 Bb4? 12 a3 Ba5? 13 b4 f5 14 Ned2 Bb6 15 c5 e4 16 Nh4 e3 17 Ng6?! Qg5 18 Bd5 Rf7 19 Bf7 Kf7 20 Nf8 Kg8 21 Nf3 Qf6 22 cb ef 23 Rf2 ab 24 b5 Nd8 25 Ng6 Qg6 26 Rc7 f4 27 Nd4 fg 28 Rg2 Qd6 29 Qb3 Kh8 30 Qc3 gh 31 Kh1 Qf6 32 Rg7 Bh3 33 Rg8 Kh7 34 R2g3 Bd7 35 R8g7 Qg7 36 Rg7 Kg7 37 Qc7 Nf7 38 Qd7 Ra3 39 Nf5 Kf6 40 Qe7 Kf5 41 Qa3 h5 42 e4 Kg6 43 Kh2 h4 44 Qe7 Ng5 45 Qb7 And I assumed that not even the Challenger 9 could lose this position. My conclusion is that probably the 5 MHz machine would eventually win the majority of games in a match but that the older machine is definitely the finer chess player. The 5 MHz machine's faults are: tends to accept the 'bad bishop', accepts bad pawn structure without compensation, unable to find a non-destructive move in positions in which constructive moves are difficult to find, on the other hand it seems much better tactically. In the above games, the older Challenger 9 quickly gained winning advantages but in both cases lost a good deal of its advantage due to the 'horizon effect'. For me the solution is somewhat simple: I can have to two machines play in 'consultation' against me. But a deeper problem is why the software was modified away from playing good 'classical' chess to more powerful, deeper searching of tactical possibilities; this second option would give it a higher rating when measured against other machines but I think an improving beginner would find the 5 MHz Machine far easier to beat than the older Fidelity Challenger 9. Thus while it could be claimed that it is a stronger machine, it seems to be a much weaker player.
davet@oakhill.UUCP (Dave Trissel) (03/27/85)
In article <73@milford.UUCP> bill@milford.UUCP (bill) writes: > >About a week ago the 5 MHz Fidelity Challenger which I had ordered >from the USCF arrived and I was rather disappointed with its play >against me, .... > >The 5 MHz machine's faults are: tends to accept the 'bad bishop', >accepts bad pawn structure without compensation, unable to find a >non-destructive move in positions in which constructive moves are >difficult to find, on the other hand it seems much better >tactically. > >But a deeper problem is why the software was modified away from >playing good 'classical' chess to more powerful, deeper searching of >tactical possibilities; this second option would give it a higher >rating when measured against other machines but I think an improving >beginner would find the 5 MHz Machine far easier to beat than the older >Fidelity Challenger 9. Thus while it could be claimed that it is a >stronger machine, it seems to be a much weaker player. Having produced my own chess program I can make some educated guesses. First, consider that the vast majority of chessplayers buying computer chess machines are not that high rated a player-usually beginners. The higher a persons rating, the fewer there are and less of these would be interested in fiddling with micro chess playing machines. Second, the new weaknesses you pointed out would seem to all have a direct bearing on move search time. Lets take for example, pawn structure. Just to make sure that pawns are still linked after an exploratory move (not even considering whether they're 'properly' linked for the given position) requires a numerical evaluation factor be produced by examining for each pawn four (or six) surrounding squares for other pawns of like color. Take the bad bishop detection. Its easy for a human to look at the board and recognize a bad bishop and its obvious when considering moves whether they impact such a status. But a computer program must do costly scans accross the board to determine such a thing. And it would have to redo the scan thousands of times during a move evaluation. Now, I am simplifying things a bit since there are programming tricks to shortcut some of this. But the problem remains that even the simplest 'extra' check added to a chess programs move evaluation can have a severe impact on the number of nodes (moves) evaluated. Third, the horizon effect critically impacts chess strength, especially at lower ply levels that the micros are running at. Therefore, there is the constant conflict of "Will improving our program's chess 'knowledge' overcome the weakness added due to shorter horizon forced on our search tree?" Yet another reason to improve search depth is that the micro people would just LOVE to beat BELLE or CRAY BLITZ, and they really don't have a ghost of a chance unless their ply search depth as within a couple plies of those monsters. (In other words, no amount of chess smarts at 5 ply will beat a dumb machine running 9 ply. The 5 ply machine will start losing pieces due to tactical miscalculations.) Following the computer chess manufacterers like Fidelity over the years, one can see how the various generations have gravitated first to one side and then the other Finally, I think you hit the nail on the head when you mentioned that the new machine may well beat other machines even though its chess games may not end up being as useful to a human learning chess. There are several entries in the marketplace, and with such fine margins of profit a dramatic loss at a well recognized tournament against a competitor can well hit the money belt for a year or more. In summary, there are several nasty tradeoffs which must be made in deciding the "personality" of a computer chess program. I hope my "guesses" shed some light on the subject. Dave Trissel {ihnp4,seismo,gatech}!ut-sally!oakhill!davet