csmath: 8. Be3
[New move but 6. c4 is already highly original sideline barely ever played on the top level. Fianchetto version would indicate intent of black to play kingside attack, however Andreikin will never start anything here.]
13. d4
[this move is prompted by previous move of black (12. ...Na6). White is also trying to reach queen-pawn opening structures probably because of familiarity with KID and Grunfeld.]
17. ... Ncd7?
[This natural move is an error because it allows white to target the bishop on e6 immediately.]
18. Ng5! Qc7
19. f4!
[Svidler immediately punishes the error of black.]
19. ...Qa5!?
[Seems natural to attempt a countergame but this is not going to work.]
20. a3 h6
21. Nf3?
[White fails to achieve bishop pair and serious advantage in the center: 21. Nxe6! Rxe6, 22. Qf2 with the threats of both c5 and f5. For example:
22. ...Rae8
23. c5! dxc5
24. Bxf6 Nxf6
25. e5 Nd5
26. Nxd5 cxd5
27. Rxd5 b6?
28. Bb3
and the difference in strength of bishops is obvious.]
21. ...Nh5?
22. Bxg7 Kxg7
23. Qd2
[Very natural response that indirectly protects c4 square for example 23. ...Qc7?, 24. f5! gxf5, 25. gxf5 and black loses bishop.]
24. ...Bxc4?!
[Both pawns on c4 and on b2 are poisoned but c4 is really a viper. The next move by white should have been quite obvious to black. Better alternative: 24. ...Qxb2 25. f5! gxf5 26. exf5 Bxc4
27. Qd4+ Nhf6
28. Qxc4 d5
29. Qd3 Qxa3
30. Nd4
and white has piece for three pawns. He is clearly better but the position is playable for black. Open position of black king was surely not appealing to Andreikin.]
25. Na4 Qc7
25. Qc3+ Nhf6?!
[One more error in the position black cannot afford any more errors. 25. ...Kg8 26. Qxc4 b5 27. Qb4 bxa4 28. Rxd6 Rab8
29. Qd2
with probably decisive advantage.]
30. ...Red8
[responding to threat e5 but it is not good enough. Black has no defence for example in case of 30. ...Nf8, 31. Rxf6! Kxf6, 32. Ne5 and white will return the exchange easily plus two more pawns.]
31. e5!
[anyway and the game is now decided while white crashes last defences around black king.]
31. ...Ne8
32. Qc3 [obvious threat] Nb6
[and black is completely lost.]
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This is a very complex game in which Svidler played the best game in Russian Championship so far. He has obviously displayed high level of mastery here and completely outplayed Andreikin in the middlegame.