Thursday, March 22, 2018

Comebacks part 3

In 2 years time my son Hugo managed to eliminate his original material-handicap. We started with 23 points (1 pawn = 1 point) as odds (see strange material balances part 2). Today only a (heavy) time-handicap (18 minutes against 1 minute and 15 seconds) remains. I find this surprising as I expected to still give bigger odds because I am almost 1000 points stronger. My son Hugo has only moderate technical skills so this situation is very different compared to the handicap-match against the Dutch expert Jaap Amesz which I mentioned in my article swindles.

I warned in my article sacrificing that often we sacrifice too optimistically. Today I want to refine my view by adding that even a small material-advantage in most cases will be decisive. Except beginners still dropping pieces, we very rarely see players recovering from a material-disadvantage. This sounds contradictory to what I wrote in my article comebacks. In that article I talked about 11 out of 100 of my games a deficit of 3 points was caught up. In 7 games even a comeback of more than 6 points happened with 2 extreme cases of 29,67 and 32,06 points.

The reason is that a computer-evaluation very often strongly deviates from the material-position on the board. Their evaluation is the final result of the critical line after both sides made the best moves. This final-position can deviate a lot from the actual position in terms of material if we are dealing with tactics. Sometimes those variations are extremely complex, making the engine-evaluation losing its connection to the practical chances on the board see annotations. It is another example of what I already described in my article to analyze using a computer part 2. An engine helps you to define very quickly your errors but then you still need to add the right interpretation to those mistakes. Unsurprisingly this often goes wrong, creating frustrations and aversion from the engines.

The difference between an engine-evaluation and a material-balance is clearly shown when looking at the comebacks. To illustrate this properly I again used the same 100 games of my initial article about comebacks. However I didn't just count the pieces on the board to make my investigation. Only when there was no clear compensation, I took the material-difference into account. Gambits or theoretical drawn positions can't be considered as comebacks. Below we see first the summary of my opponents.

Next is the summary for myself.

Only 5 pawns were recovered by my opponents in a total of 36 comebacks. I made up 13 points spread over 38 comebacks. So in most cases a pawn down meant a loss. Beside the exceptions can be almost exclusively linked to special cases. Or the position is tactically very sharp so a higher probability exists to recover from a small material disadvantage see my article the einstellung effect. Or the material is already very reduced so a higher probability exists to reach a theoretical drawn-endgame see e.g. my article practical endgames.

We can also assume from above tables that rating barely has any effect at the material-balance. I experienced this end of last year in a very painful defeat. I was obliged to win the last round of the maneblussers-tournament to get the tournament-victory and with the 1900 rated player Dries Janssen as opponent my chances looked bright in advance. However in an obscure opening-line I totally misplayed my position and very early lost a piece without any compensation.
[Event "Maneblusserstornooi 7de ronde"] [Site "?"] [Date "2017.??.??"] [Round "?"] [White "Janssen, D."] [Black "Brabo"] [Result "1-0"] [ECO "A04"] [WhiteElo "1930"] [BlackElo "2310"] [SetUp "1"] [FEN "rn5r/pppqbkpp/3p4/3Np1P1/2b3Q1/7P/PPP2PB1/R1B1K2R w KQ - 0 16"] [PlyCount "73"] [EventDate "2017.??.??"] [CurrentPosition "rn5r/pppqbkpp/3p4/3Np1P1/2b3Q1/7P/PPP2PB1/R1B1K2R w KQ - 0 16"] 16.Qxc4 { (Here I strongly considered to resign and that was definitely possible as the engine already shows an advantage of +6. I keep on fighting still for many moves and almost get counter-chances but the handicap was eventually too big.) } 16...Qe6 17.Qb3 Na6 18.Qxb7 Nc5 19.Qc6 Rac8 20.O-O Qf5 21.f4 e4 22.b4 Ne6 23.Ne3 Nd8 24.Qc4+ Qe6 25.Qxe6+ Kxe6 26.Bxe4 Rb8 27.Rb1 h6 28.f5+ Kd7 29.f6 gxf6 30.gxf6 Rg8+ 31.Kh2 Bf8 32.Bf5+ Kc6 33.b5+ Kc5 34.Be4 d5 35.Ba3+ Kd4 36.Nf5+ Ke5 37.Bb2+ Ke6 38.Bd3 Kf7 39.c4 Ne6 40.cxd5 Nc5 41.Bc4 Bd6+ 42.Nxd6+ cxd6 43.Rbe1 Rbe8 44.Bd4 Ne4 45.Rg1 Nd2 46.Rxg8 Rxe1 47.Rg7+ Kf8 48.Re7 Rc1 49.Be2 Rc2 50.Kg3 Rxa2 51.Bh5 Kg8 52.f7+ { (Mate follows. A painful defeat as not only I missed the tournament-victory but I also lost all the rating which I nicely gained during the last months.) } 1-0
Despite white surely didn't play the most quickest win, never the result was put in question. The handicap was far too big to ever hope to comeback. Besides my opponent wasn't a beginner either. Resignation immediately after losing the piece was a valid choice but something I couldn't cope with at that time. Also don't forget that it was 18 years ago that I lost another standard-game against a -2000 rated player see my article White chooses in the opening a drawing-line.

So you better don't get behind or your name must be Magnus Carlsen. Anish Giri didn't pass the opportunity to write a funny tweet about it: The world champion Magnus Carlsen is now officially a full piece stronger than the rest of the mankind. In other words Magnus can win against anybody even with a heavy handicap of a full piece.
[Event "Tata Steel"] [Site "Wijk aan Zee NED"] [Date "2018.01.21"] [Round "8"] [White "Magnus Carlsen"] [Black "Gawain Jones"] [Result "1-0"] [ECO "B76"] [WhiteElo "2834"] [BlackElo "2640"] [SetUp "1"] [FEN "r1bqr1k1/p5bp/2p3p1/3nppN1/2B5/4BP2/PPP3PP/1K1RQ2R w - - 0 17"] [PlyCount "51"] [EventDate "2018.01.12"] [CurrentPosition "r1bqr1k1/p5bp/2p3p1/3nppN1/2B5/4BP2/PPP3PP/1K1RQ2R w - - 0 17"] 17.g4 { (A colossal blunder which should normally always lose the game.) } 17...f4 18.h4 fxe3 19.Qxe3 h6 20.Qc5 Bb7 21.Ne4 { (White is a piece down against a pawn and has no compensation whatever. Still Magnus manages to win the game.) } 21...Re6 22.h5 Qb6 23.g5 hxg5 24.Qa3 { (In the meanwhile white has full compensation for the piece.) } 24...Rb8 25.b3 Qd8 26.Qxa7 gxh5 27.Rxh5 { (White is winning already.) } 27...Rg6 28.Rxg5 Rxg5 29.Nxg5 Qc8 30.Rg1 Ra8 31.Qb6 Ra6 32.Qc5 Qd7 33.Ne4 Kh8 34.Qf2 Qe7 35.Bxa6 Bxa6 36.Qh2+ Kg8 37.Qh6 Qa7 38.Qe6+ Kf8 39.Rg5 Ne3 40.Qd6+ Kf7 41.Nc5 Bc8 42.Rxg7+ 1-0
Exceptions proof the rule. Miracles happen sometimes at chess so you do wonder if maybe it makes sense to continue always till mate. The American grandmaster Grigory Serper showed some other miracles in his article Why you should never resign? but leaves it up to the reader to decide when to resign or not at all. Personally I think it is dubious and mainly a waste of time to continue 100 lost games till mate just to steal 1 extra half point.


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