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Tuesday, June 2, 2020

Head Whirling Complications By Rossolimo

     At Venice 1950, Alexander Kotov and Vasily Smyslov demonstrated their outstanding skill, but their decisive first and second would be would have been more or less expected. 
     New Zealanders were especially proud of Robert Wade’s success who said of his result that it was to be “regarded as an advance of his previous pIay." Wade bagged a best game prize, drew his game with Smyslov and finished tied for fifth place. Wade played many strong events in 1949 and 1950 and drew a 1950 match against Lothar Schmid at Bamberg by 5–5, and eventually settled in England. 
     In what seems a rather unusual circumstance Rossolimo was awarded a Brilliancy Prize for his game against Nestler even though it was a draw. 
 
Nestler
   Vincenzo Nestler (January 8, 1912 – July 15, 1988) was an Italian master. He won the Italian Championship twice: at Florence 1943 and Trieste 1954 (after a play-off); he finished second four times: (1937, 1953, 1956, 1959). He played for Italy in Olympiads at Dubrovnik 1950 and Helsinki 1952. 

     There was a note to the game in the December 1950 issue of the New Zealand magazine Chessplayer stating that when Rossolimo played 35.Kb2 he was in time trouble and added that not knowing the Italian version of the FIDE rules which stated both a player and his opponent could claim the draw, he later allowed the position to occur three times. 
     The threefold repetition rule states that a player can claim a draw if the same position occurs three times, or will occur after their next move, with the same player to move. The repeated positions do not need to occur in succession. The game is not automatically drawn if a position occurs for the third time – one of the players, on their turn, must claim the draw with the arbiter. Even if the claim is incorrect, any draw claim is also a draw offer that the opponent may accept. 
 
Rossolimo
   Draws by this method used to be uncommon. At various times the rule has been variously formulated. For example, Tim Harding's notes to a correspondence game between the cities of Pest and Paris played between 1842 and 1845 state that a sixfold repetition was necessary to claim a draw. 

     The rules for the first official World Chess Championship 1886 match between Wilhelm Steinitz and Johannes Zukertort stated: ... if both players repeat the same series of moves six times in succession, then either player may claim a draw. The rule was modified soon afterward to be based on positions instead of moves, and for three repetitions. 
     The first use of a rule on repetition was in a tournament in London in 1883, which stated: ...if a series of moves be repeated three times the opponent can claim a draw. 
     As to what rules were in effect at Venice and why Rossolimo was unaware of them, I am not sure. 
Kotov's tree of analysis
     In his book Think Like A Grandmater, Kotov spends considerable time analyzing the position after the alternative 23...Qd6. 
     In analyzing this game I was using a my smaller two core laptop and was switching back and forth between Stockfish and Komodo running on a single core. The result was a not very accurate evaluation of the positions resulting after 29.Kf1 as the engines gave different evaluations that shifted as moves were actually made and time increased or decreased. Evidently a true evaluation is going to require a LOT of time and digging very deeply into the position.



Nicolas Rossolimo - Vincenzo Nestler

Result: 1/2-1/2

Site: Venice

Date: 1950

Sicilian Scheveningen

[...] 1.e4 c5 2.♘f3 e6 3.d4 cxd4 4.♘xd4 ♘f6 5.♘c3 d6 The Scheveningen is characterized by black setting up a small center with pawns on d6 and e6. There are numerous move orders that reach the Scheveningen. 6.♗e2 The classical approach. Keres' 6.g4 is more enterprising. 6...a6 7.O-O ♕c7 8.f4 ♘c6 9.♗e3 ♗d7 10.♕e1 b5 11.a3 ♘xd4 The only move that gets the stamp of approval here is 11...Be7. 12.♗xd4 ♗c6 13.♗d3 (13.♗xf6 was stronger. 13...gxf6 14.f5 with the initiative.) 13...♕b7 This attack on the e-Pawn is easily met and so first playing 13...Be7 and castling was better. 14.♕e2 He could still play 14.Bxf6 with good effect. 14...♘d7 15.b4 e5 TYhe ; point of his last move, but white already has a slight advantage. 16.fxe5 dxe5 17.♗e3 ♘f6 18.♖f5 ♕c7 Once again delaying castling is not advisable. 19.♖af1
19.♘d5 was a good alternative. 19...♘xd5 20.exd5 ♗xd5 21.♗f4 ♗d6 22.♗xe5 O-O-O and white is better.
19...♗e7 Here white can keep a slight advantage with 20.Qf3 O-O 21.Bd5 or 21.Bxf6, but Rossolimo is already planning his double exchange sacrifice which leads to crazy complications. 20.♖5f2 O-O 21.♖xf6 This first sacrifice of the exchange is a brilliant human concept, but actually it results in no more than equality because there is no forced decisive followup and black can find adequate defensive resources. Another very interesting move that results in a lot of complications is 21.g4 21...♗xf6 22.♖xf6 The seconde exchange sacrifice is now forced as on other moves it's black who has the advantage.
22.♘d5 ♗xd5 23.exd5 ♗e7 24.♕f3 ♖ad8 and white has nothing to show for the exchange.
22...gxf6 23.♘d5 Rossolimo has made a double exchange sacrifice, both of which were based on intuition, but to some extent could be backed up by calculation. In any case, if black finds the right move here (which Nestler does) the position is quite equal. 23...♗xd5 Best. At this point the evaluate by Komodo is 0.00. Had black played 23.. .Qd6? he would have had a lost position although I think that while for for GMs and engines that might be true, for amateurs it would be quite difficult for us to prove it.
23...♕d6 This move was analyzed in great detail by Kotov in Think Like a Grandmaster, and the complications are very great. The best line according to Stockfish is: 24.♕h5 f5 25.♗c5 ♕e6 26.♕g5 ♔h8 27.♗xf8 ♕g6 28.♗e7 ♕xg5 29.♗xg5 According to Komodo white has a winning advantage with an evaluation of about 2.5 Pawns. 29...♔g7 30.♗f6 ♔f8 31.♔f2 ♖e8 32.g4 fxg4 33.♘c7 ♖c8 34.♘xa6 ♖a8 35.♘c5 ♖xa3 36.♔g3 ♖a1 37.♔xg4 ♖b1 38.c3 ♖b2 39.h4 ♖d2 40.♔f5 h6 41.♗xe5 ♖f2 42.♔g4 ♗e8 43.♗d4 ♖g2 44.♔h3 ♖a2 45.♔g3 ♔e7 46.♔g4 ♖g2 47.♔f5 ♖g6 48.♔f4 And here the position is evaluated as 4 Pawns in white's favor.
24.♕g4 ♔h8 25.♕f5 ♖g8 26.♕xf6 ♖g7 27.♗h6 ♖ag8 28.exd5 At this stage Komodo evaluates the position at dead equal whetyher black plays 28...Qc3, 28...Qa7+, 28...e4, 28...Qd7 or probably any other reasonable Q move. 28...♕c3 29.♔f1 Here things get complicated. Stockfish suggests a draw (0.00) after 28...Qa1+ and evaluates black's next move as a mistake at a magnitude of almost two Pawns. Komodo on the other hand evaluates 30.d6, 30.Be4 and 30.Bxg7+ at 0.00. Whom should we believe?! 29...♕d4 30.d6
30.♗xg7 ♖xg7 only draws by a perpetual after 31.Qd8+ and after 31.d6 ♕d5 white can make no process.
30...♕d5 31.♗f5 ♕xg2 32.♔e1 ♕g1 Another critical position for the engines. Komodo says its 0.00 after either 33.Kd2 or 33.Ke3. Stockfish wants to gove whitre a 2.5 Pawn dvantage after either move. 33.♔d2 ♕f2 34.♔c1 ♕g1 35.♔b2 ♕d4 The first position in the threefold repetition. 36.♔b1 Throwing away his advantage. Winning is 36. c3.
36.c3 ♕f2 37.♔b3 and black is out of checks, he will lose the exchange and some PS all of which combine to give white a won position. 37...♕b6 38.♕xe5 a5 39.♗xg7 ♖xg7 40.d7 a4 41.♔b2 ♕d8 42.♕xb5 etc
36...♕d1 37.♔b2 ♕d4 The second position in the threefold repetition. 38.♔a2 Again, white is winning after 38.c3!! 38...♕d5 39.♔a1 ♕d1 40.♔a2 ♕d5 41.♔b1 ♕d1 42.♔b2 Yet again, white is winning after 42.c3!! but this move allows the third repetition. 42...♕d4 Here Nestler claimed the draw. If he hadn't guess what move available to white would win. If you said 43.c3 give yourself 2 bonus points.
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