After playing a couple of games playing Sicilian against a computer (had no wifi) i’ve noticed that I have been able to create much better pawn structures than against players that would be similarly ranked. Why is this?


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1.e4 c5 2.b3 d6 3.Bb2 Nf6 4.Bb5+ Bd7 5.Nc3 Bxb5 6.Nxb5 a6 7.Na3 Nc6 8.d3 b5 9.Qe2 b4 10.Bxf6 bxa3 11.Bh4 f6 12.Qd1 g5 13.Bg3 h5 14.f3 Bg7 15.c3 e6 16.Rc1 f5 17.Nh3 f4 18.Bf2 Bf6 19.Ng1 O-O 20.Qc2 h4 21.Qd1 Rf7 22.Qd2 Rb8 23.Ne2 a5 24.Qd1 h3 25.O-O Rh7 26.gxh3 Qd7 27.Be1 Rxh3 28.Rc2 d5 29.Nc1 dxe4 30.Rg2 e3 31.d4 Qd6 32.Qc2 Kh8 33.Ne2 Rd8 34.Kh1 a4 35.b4 cxb4 36.Ng1 Rh7 37.Qb1 b3 38.axb3 axb3 39.Qxb3 e5 40.Ra2 exd4 41.cxd4 g4 42.Qxa3 g3 43.Qxd6 Rxd6 44.d5 Ne7 45.Rg2 Nxd5 46.Re2 Ra6 47.Bxg3 fxg3 48.Rg2 Nf4 49.Rxg3 Ra2 50.h3 e2 51.Re1 Bc3 52.Rxe2 Nxe2 53.Rg2 Rg7 54.Rxe2 Rxg1+ 55.Kxg1 Rxe2 56.Kh1 Bd4 57.f4 Kg7 58.h4 Kg6 59.h5+ Kxh5 60.f5 Kg4 61.f6 Kg3 62.f7 Re1# 

Several points regarding your question:

Cannot compare computer and human rating

In your question you compare a computer with "players that would be similarly ranked."

However, the rating systems used in chess only describe the relative strength among players from the same pool. So a FIDE rating only tells you how strong you are relative to other FIDE rated players. An online rating from say lichess only tells you how strong you are relative to other lichess players, a computer rating only tells you how strong the computer is relative to other computers. In order to get comparability, you would need lots of computer-human rated games, which is not done.

So the computer may in fact play at lower absolute strength than you think based on its (computer) rating.

Many factors determine absolute strength

Chess is complicated enough that many factors determine "absolute strength". One (human) player might be blundering pieces now and then, another might be very weak in positional play, etc. Still they could end up having the same rating. So it might be very well that one player lets you build a very nice pawn structure and still beat you now or then.

There are many ways to cripple an engine

If you are a programmer, aiming for the strongest engine is a well defined task. However in your case you obviously played against a weakened engine.

If you are asked to reduce the strength of an engine, there are many ways to do this. You could just limit the search depth, which would make it vulnerable to tactics; or you could make the engine blunder pieces occasionally; or you could remove (or lower the weight) of one of the factors in the evaluation function. For instance if you remove the part which is relevant for "king safety", the engine might neglect the safety of its king.

It seems the programmer of your engine chose to reduce the relevance of "piece activity" and/or "space control". However another programmer might have chosen another way to reduce the strength. That's why I am not sure that your findings should be generalized to all computer engines.

Regarding the sample game

I would not describe this as "allowing to create a much better pawn structure". In fact at some point around move 12, you have a rather weak pawn structure with lots of weaknesses on the light squares, because your pawns are all on dark squares. Typically, if you have only one bishop left, you put the pawns on the squares of opposite color to that on which the bishop operates. This way the pawns are not in the way of your bishop and also you cover both, dark and light, squares with bishop+pawns.

As mentioned above, to me the white side's play looked very passive. At some point the computer was moving his pieces only on the first and second rank, waiting for something to happen.


This is a semi-guess but perhaps its because computers make "robotic" moves where a human would maybe try and trip you up by playing an odd-ish move instead of the standard "lemme consult the computer program" type of idea. I think it was Kasparov who said computers win by "brute force." Humans have more flair, more creative oddities.

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