woldsmandriffield: After Liren's under-promotion of the e-pawn to Knight the players reached the following position.  click for larger viewCompare this with the position given by Averbakh in his Chess Endings: Essential Knowledge (if you can get hold of a copy for your library & can find time to study the 5 short chapters, your confidence in tournament play will grow should you face an ending!).  click for larger viewAfter 1..Kf6 Averbakh gives the line 2 Nh7+ (only move: 2 Kh8 Re8 3 Kg8 Rd8 and mates) 2..Kg6 3 Nf8+ Kh6 4 Kh8 Rf7 5 Kg8! (5 Ne6? Rf6 mating) 5..Rg7+ 6 Kh8 Rg1 7 Nd7! Kg8 8 Kg8 and Black can make no progress. Averbakh's observation on this ending is worth remembering: "Thus, in the ending of Rook against a Knight it is not dangerous for the King to be confined to the edge of the board." Back to Topalov vs Liren. Topalov defended perfectly, keeping his King & Knight close together, until the following position was reached on move 96 leading to the final test question.  click for larger viewYOUR MOVE
The only drawing move is 96 Nc7 which is the exact equivalent to 7 Nd7 in the Averbakh example given above. If Liren had gone 97 Kf6 then just 97..Kf8, while if 97 Kh6 the safest reply is 97..Ne8 It may be of some comfort to Topalov that others have gone wrong in similar positions. A relevant example is Berg vs Kuijf, 1990:  click for larger viewSafest is still 1 Nc7! Berg played 1 Nd6? which loses. Ironically, he could alternatively have drawn with 1 Ng7 - the reason is subtle and will be explained later. Before we get to this, here is a second key position given by Averbakh (rotated 90 degrees with colours reversed):  click for larger viewBlack (to move) wins with 1..Rg5 2 Kh7 Kf7 3 Kh8 Rg1 4 Nh5 Rh1. Averbakh's comment: "This position was known as far back as the ninth century." After 96 Ng7? we saw 96..Kf6 and now 97 Kf8 Rf1 98 Ne8+ Ke6!+ 99 Kg8 Ke7 100 Ng7 Rg1 101 Kh7 Kf6! (care is needed 101..Kf7 102 Nh5 Rh1 103 Kh6 and White escapes!) so Topalov chose 97 Nh5+  click for larger viewThe fact that ..Ke6..Ke7 is a winning plan in similar positions probably explains why Liren slipped up with 97..Ke6? here. Best is the far from obvious 97..Kf5! 98 Ng7+ Ke5! 99 Ne8 Ke6 100 Ng7+ Ke7 101 Kh7 and now 101..Kf6! wins as before. In the Berg vs Kuijf game, the Black Rook stands on f1 and so ..Kf5 isn't possible due to the fork on g3: hence Ng7 still draws (!) - but don't rely on nuances like this. Take Averbakh's advice and go Nc7 every time! Tragically for Topalov, after 97..Ke6 he missed the last drawing chance: 98 Kg7! (gaining breathing space enabling the King and Knight to join together successfully). There were no further opportunities and Liren's play in the closing phase is very instructive as he drives the King and Knight apart. |