When Adams played Topalov in 1996, the game went
White now transposes back into Adams-Topalov.
15. Bf2 was preferred by Adams but after 15... Qf4+ 16. Be3 Qg3 the game is even. In fact, Topalov played 16...Qf6?! Playing Tonu Oim, I would have played 16...Qg3 and been glad of the draw, if offered. He, however, had other ideas.
Here Topalov suggests 16 Nbc7 Bxd5! 17 Nxd5 Rfe8, but Oim played
This novelty prevents 16...Bxd5 and keeps the other knight on b5, threatening Black's queenside but neglecting the centre. [In Tallinn shortly after this game ended, the world champion told Tim Harding he would never had played this move had he owned a computer to check it.]
This blocks the Dragon diagonal, but Black can now gain control of the d-file with the rook at present on f8.
Played with the intention of ...Ng3.
The white rook is now trapped, but how to attack it? A bishop on e3 would do the trick, so
Removing the only cover
White had expected to lose material with (23...Nxf1 line)
Black simplifies the endgame. Bishop and Knight against Knight should win, in spite of White's queenside pawn majority.
Creating a square for the e pawn to advance to and intending an eventual ...Ke6. Also threatening, of course, 32...Nc1.
Fixing the white a- and c-pawns
ED: White offered a draw here.
It is essential in such an endgame to ensure that one's opponent has no counterplay. Now the black king can advance and White's move possibilities are restricted. In particular, there is no longer the threat of Ng5+ when the black king goes to e6.