Author: Ricardo Gibert
Date: 12:09:39 10/06/03
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On October 06, 2003 at 15:05:18, Ricardo Gibert wrote: >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 Oops! This should be 5.Nf3 Ng5 6.d4 exd4 7.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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