27 August 2016

Commentary: 2016 World Junior Championship, Round 12 (Bersamina - Xiong)

This very recent game caught my eye, as a victory by the new World Junior Champion, American GM Jeffery Xiong.  Ranked first in the world U16 category, Xiong in round 12 clinched the title by winning as Black against IM Paulo Bersamina.  I had an initial interest in the game because it (a Grand Prix Sicilian) turns into what could be considered a reversed English Opening, making its subsequent play full of ideas that are directly relevant to my opening repertoire.  There are a lot of more general lessons contained here, though, including the importance of time and development in the opening and early middlegame (which White ignores on multiple occasions), the value of the initiative, and some interesting tactical ideas.  White essentially takes a wrong turn with his plans on move 11, offering to sacrifice a pawn with very little compensation, but Xiong passes up simpler ways of exploiting this in favor of more complex play, which seems to be an intentional strategy.  Xiong's endgame technique and ideas are also worth looking at, in terms of how to win a won game.
[Event "World Junior Open 2016"] [Site "Bhubaneswar IND"] [Date "2016.08.20"] [Round "?"] [White "Bersamina, Paulo"] [Black "Xiong, Jeffery"] [Result "0-1"] [ECO "B23"] [WhiteElo "2402"] [BlackElo "2633"] [Annotator "ChessAdmin/Komodo 9.3"] [PlyCount "155"] [EventDate "2016.??.??"] 1. e4 c5 2. Nc3 d6 3. f4 Nc6 4. Nf3 g6 5. Bb5 Bd7 6. O-O Bg7 7. Bc4 {this seems like a bit of a waste of time in the opening, especially after the next move. Presumably it was done to preserve the bishop from exchange.} Na5 8. Be2 Nf6 {this looks like it makes the knight a target for an advance of the e-pawn, but that would not turn out particularly well for White.} 9. Qe1 {at around 48 percent, this scores better than anything else for White in the database, but it's still not a good thing. Black has fully equalized already while White continues to lose time in the opening.} (9. e5 dxe5 10. Nxe5 (10. fxe5 $6 Ng4 $17) 10... O-O $11 {and Black has a comfortable game.}) 9... Nc6 10. Bc4 { inviting a repetition of moves, although Black can do better.} Nd4 (10... O-O $5 {the engine suggests castling first, which looks safer.} 11. d3 Nd4) 11. Qh4 $6 {this doesn't work and I'm not sure what White was looking to do here by offering the c2 pawn as a sacrifice. Even simply castling in response is fine for Black.} (11. Nxd4 {simplest appears best here.} cxd4 12. e5 dxc3 13. exf6 Qb6+ 14. Rf2 Bxf6 $11) 11... b5 {an interesting idea that further complicates the game and keeps the tension up, which is probably what Xiong wanted.} (11... Nxc2 12. Rb1 Nd4 $17 {and White doesn't have any real threats. For example} 13. Ng5 $2 (13. b3 $17) 13... d5 (13... e6 {is also sufficient}) 14. Nxd5 Nxd5 15. f5 (15. Nxh7 $2 {the knight is pinned here and Black now has a free hand.} Nb6 16. b3 Nxc4 17. bxc4 Bc6 $19) 15... Bf6 $19) (11... O-O 12. f5 $5 {should be OK for Black, but gives White at least the appearance of some initiative.}) 12. Nxd4 cxd4 13. Nxb5 Qb6 {Black has (temporarily) invested a pawn, but has the initiative in return.} 14. a4 a6 15. a5 Qc6 16. Na3 Nxe4 {now Black has his pawn back and a favorable position, while White's pieces are uncoordinated and he lacks an obvious plan to make progress.} 17. d3 Nf6 18. Nb1 {an excellent illustration of how time in the opening and early middlegame can be valuable. The knight has journeyed back to its original square, with associated tempo loss, while Black can now make progress in the center.} (18. Bb3 $5 $15 { would clear the c4 square for the knight instead.}) 18... d5 19. Bb3 Qc5 { this avoids having White play Ba4. While d6 seems like a more useful square for the queen, being less limited, Xiong no doubt had the next knight maneuver to e3 in mind, which the queen supports.} 20. Re1 Ng4 21. Re2 Ne3 {Black would be quite happy to have White capture the knight, thereby undoubling the Black d-pawns and giving him a passed pawn on e3.} 22. h3 {another time-wasting move. } (22. Nd2 $5 {White really needs to get more of his pieces into the game.}) 22... O-O {White now has no prospects on the kingside and it's about time to get the king to safety away from the center.} 23. Qe1 Rab8 {activating the rook; Black wants to play with all of his pieces. This may seem to ignore White's last move, which adds pressure to the Ne3, but it still cannot be taken without benefiting Black.} 24. Ra3 {again a move illustrating how awkward White's position is.} (24. Bxe3 dxe3 {opening up the long diagonal and the d4 square for the Bg7} 25. Rxe3 $2 Bd4 $19) 24... Rfc8 $19 {by this point White is under huge pressure, which will simply get worse, and can do nothing about it.} 25. Kh1 {moving off of the g1-a7 diagonal and taking away the ... Bd4 tactic, but it still doesn't help much.} Bf5 26. Bxe3 dxe3 27. Rxe3 Bxb2 28. Ra2 Bd4 {Black can again safely ignore White's threat to pick up a pawn, in this case on e7.} 29. Rf3 (29. Rxe7 Bf2 $1 {and now wherever the queen moves, the Re7 will be left hanging, or White opens himself to back rank problems.} (29... Bxd3 {would also be sufficient, as the Bb3 would be hanging after a recapture on d3}) 30. Qe2 (30. Qd2 Rxb3 31. cxb3 Qxe7 32. Qxf2 Rc1+) 30... Rxb3 {winning the piece, as if} 31. cxb3 $2 Qc1+ $19) 29... h5 {stopping g4 to kick the Bf5} 30. Nd2 {White finally gets all of his pieces developed, on move 30.} Bc3 31. Qf2 e6 {an instructive decision. Black heads for the endgame, which he must be confident of winning, as he will pick up the indefensible a5 pawn in the process.} 32. Qxc5 Rxc5 {After the exchange of queens Black wins the a-pawn and the game is practically over.} 33. Nf1 Rxa5 34. Rxa5 Bxa5 {Black has the outside passed a-pawn, the two bishops, and a well-placed rook, which should (and do) lead him to victory from this point on. } 35. Kh2 Bc3 36. g3 a5 {passed pawns must be pushed!} 37. Ne3 {designed to support the g-pawn advance} Rb4 {Black can also just make a waiting move with the bishop here, such as ...Bg7. This would remove White's subsequent threat along the third rank with the rook, although it perhaps doesn't matter in the end.} 38. g4 hxg4 39. hxg4 {Black can now play this several different ways. The problem for White is that his bishop is trapped after ...a4} Bxd3 40. Ng2 a4 41. Bxa4 Be4 42. Rxc3 Rxa4 {Black is still winning comfortably after the end of the sequence - remaining a pawn up, with a strong bishop vs. knight, and one pawn island versus two. However, those of us with lesser endgame technique might not have chosen this particular path.} 43. Ne1 Ra1 44. Re3 Rc1 {the ideal spot for the rook, behind White's isolated pawn.} 45. Re2 Kf8 { time to bring the king into the game.} 46. Kg3 Ke7 47. g5 Kd6 48. Kf2 Bf5 49. Nd3 Rh1 50. Ne5 Rh2+ {once the rooks come off, the win becomes more trivial for Black.} 51. Ke3 $6 {this allows the following tactic} (51. Kf3 Rxe2 52. Kxe2 $19) 51... d4+ 52. Kd2 Rxe2+ 53. Kxe2 Kd5 {compared with the above variation, Black is significantly ahead with the d-pawn and his king position in the center. Although the f-pawn will fall, this doesn't affect Black's defense against the White pawns, as Black's king will penetrate.} 54. Kd2 Ke4 55. Nxf7 Kxf4 56. c3 d3 {White could simply resign at this point, but apparently decides to play on in the hopes of a blunder by his opponent.} 57. Nd6 e5 58. Nc4 e4 {Black has two connected passed pawns in the center, will grab the g5 pawn giving him a third passed pawn, and Black's bishop covers the c8 queening square for White.} 59. Ne3 Kxg5 {a minor piece exchange is fine for Black, since the White king can't cover all of the passed pawns.} 60. Ke1 Bg4 61. Nd5 Kf5 62. Kd2 Ke5 63. Ne7 g5 64. Ke3 Bf3 65. c4 g4 {passed pawns (especially outside ones) must be pushed!} 66. Ng6+ Kd6 67. Nh4 Kc5 68. Nf5 Kxc4 69. Kd2 {is White playing for stalemate now? Hardly seems sporting.} Kd5 70. Ke3 Ke6 71. Ng3 Ke5 72. Nf1 Kf5 {Black's king now runs around the wing to escort his outside passed pawn.} 73. Ng3+ Kg5 74. Nf1 Kh4 75. Kf2 Kh3 76. Ke3 g3 77. Nd2 g2 78. Kf2 0-1

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