Author: Ricardo Gibert
Date: 12:05:18 10/06/03
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On October 06, 2003 at 14:39:57, Robert Hyatt wrote: >On October 05, 2003 at 13:43:33, Ricardo Gibert wrote: > >>There was a discussion about the value of playing oddball lines by amateur >>programs to avoid the effective book lines of the stronger programs i.e. >>http://www.talkchess.com/forums/1/message.html?319397. I thought about this a >>little and a trick occurred to me that should work on most programs e.g. >>Ruffian. >> >>The easiest way to explain it is to jump into some examples: >> 1. e3 e5 2. e4 >> 1. c3 e5 2. c4 >> 1. d3 d5 2. d4 >> 1. d3 e5 2. d4 >> >>What is this? Isn't White just dumping a tempo? Yes, but the idea is for white >>to get the computer opponent out of book while retaining the advantage of >>hundreds of years of opening theory for your own program! >> >>It can be carried out with 2 possible motives in mind: >>1- Reach a playable middlegame with a huge time advantage on the clock. >>2- Play a sharp gambit defense in reverse. This is the idea of 1.d3 e5 2. d4 >>i.e. 2...exd4 3. Nf3 >> >>I would assume somebody has thought of this before and that some engines are >>able to handle this easily. In fact, an engine that can't I would say has a bug >>IMO. Which engines are able to cope with this trick effectively? > >I don't at the moment. I did several years ago, however. The idea is to >simply "flip" the board by changing the color of all pieces, and then swapping >everything on rank 1 with rank 8, rank 2 with rank 7, etc. Now, in the above >you end up with e4 e5 (or whatever) with white to move rather than black. You >find the move then "flip it" back to black to move. > >I quit doing it when I added book learning, as it caused some massive grief, >because even though it had found a move as book by the above trick, I didn't >do the trick in the book learning code itself as it was complicated. But it >could be done. > >It wasn't that unusual for programs to handle this years ago. I started doing >it in Cray Blitz when humans did that to it (before it was cray blitz) in the >late 1970's. It was a known "trick" that worked well. We picked up >transpositions back then because we used the same hash signature approach I >use today, where many programs did not. IE Sargon actually had a "tree" for >their book and changing the order meant both orders had to be entered into the >book or it wouldn't find the transposition. Dan/Kathe eventually went to the >same hash signature approach everyone uses today, and I'd guess they found the >same problem with e3 e5 e4. > >However, I saw a variation of this in the 1996 WCCC event with the "Ruy Lopez, >Crafty variation." e4 e5 Nf3 Nc6 Bb5 a6 Bc4. That took everyone out of book, >and yet they played the obvious developmental moves such as Nf6 and so forth. >I didn't plan it, as my "random 0" mode does a search on all book moves and >takes the one with the best score, and Bc4 came out better than Ba4 or Bxc6. >It turned out to be _much_ better as we went 20+ moves in book while everyone >else was out instantly. We ended up playing 3 programs (at least) with a 2:1 >time odds advantage (40 moves in 2 hours vs 40 moves in 1 hour) or whatever the >time control was. It was funny. > >What was _really_ funny was I had posted such a game where Crafty beat chess >genius, in my office, while tuning up for the game, and I had pointed out how >stupid the move looked to me. But I forgot about it, and it started happening >in Jakarta. I didn't know anything about it until one morning on ICC, Bruce >Moreland was asking everyone "What should I play after e4 e5 Nf3 Nc6 Bb5 a6 >Bc4?" That was the first I had heard about it. No internet access from the >Jakarta playing hall so news came out of there a day or too behind. > >Books can be funny things... By coincidence, one try I did against Ruffian went 1.e3 e5 2.e4 Nf6 3. Nc3 Bb4 4.a3 Bc5 reaching the same position in reverse! It continued 5.d4 exd4 6.Na4 playing a Two Knights defense where Black cannot play the normal Two Knights move Bb4+ due to the extra move a3.
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