Van Wely, the defending champion, overestimated the passed b-pawn that would emerge after 25...Bb4 (perhaps also the strength of his g6-bishop?), But the calculation did not work out at all. On the contrary, van Wely's manoeuvre also gave a passed pawn to Tiviakov, and his turned out to be strong as a bear:
Black's last move brings about a rather adverse change in structure. Of course Black did not want to play 25...b6 26.Nc6 here, but 25...Nc5 was possible as 26.Bxa5 would be met by Rxd4 thanks to the fork on b3.
26.Bxb4! axb5 27.a5! Extremely dangerous — but Black did not sense the danger from afar that the g6-bishop could have trouble stopping the white pawn. Now white has a solid advantage with minimal risk. E.g. If 27...Nxe5 28.a6 bxa6 O-O 30.a7 There is a threat of f3-f4 and Bf3.
27...b3 28.Nxb3 Tiviakov prepares to sac the exchange while van Wely's bishop and h8-rook are out of play. 28.Bc2
Black would be fine but for the shot which Tiviakov played in under a minute: 29.Rxd7! Rxd7 (29...Kxd7 30.Nc5+ Kc7 31.Rc1 Rd2 looks logical and offers better chances for resistance) 30.Nc5 Rd5 (and therein lies the problem: 30...Rc7 fails to 31.Nxb7! Rxb7 a6).
31.Nxb7 Rxe5 32.Kf2 Bb3 (The Bishop tries in vain to get back to d5.) 33.Rc1 Ke7 34.a6 Ra8 35.Rc7+ Kf6 36.Nd6. With a second pawn primed to reach the sixth rank, it's all over for van Wely. 36...Rd5 37.Ne4+ Kg6 38.b6 1-0
When Loek van Wely pushed his pawn to c5, everything was fine from his point of view!
Tiviakov gained his third Dutch Championship title and first since back-to-back wins in 2006 and 2007.
Translation from German: Macauley Peterson
