Yeoh Li Tian - GM Nguyen Anh Dung ending analysed

In the eight round of the Campomanes Memorial in Brunei, the following position was reached and agreed drawn.

Li Tian - Anh Dung after 42...Kxc6

This is a good opportunity to illustrate some principles of pawn endings.

1. Zugzwang
2. square of the passed pawn
3 Six rank win
4. outside passed pawn
5. distant disconnected passed pawns.

With these principles in mind, you will find it easier to play pawn endings.

In the diagram, white has potential outside passed pawn. He will never lose unless he blunders big time.

There are two possible plans to explore

The first plan will be to try to penetrate on the other side with the king. The defending side cannot venture too far away from the potential passed pawn otherwise it will be unable to return in time to stop it.

The second plan is to use the power of zugzwang and the potential outside passed pawn.
Let us try plan one first

43.Kc3 Kd6 44.Kd3 Ke7 45.Ke3 Kd6 

On e7 the black king is still within the square of the passed pawn (a4-a8-e8-e4) and can still stop the pawn if white pushes 46.b5 axb5 47. a5 Kd7 etc)

but if 45...Kf6 will lose 46.b5 axb5 47.a5+–

 46.Kf3 Ke7 47.g4 fxg4+ 48.Kxg4 f6! 

the white king must be kept from penetrating through g5 square

49.h5 gxh5+ 50.Kxh5 Kd7! 

(Black must avoid the d6 square otherwise white queens on f8 with check after 50...Kd6 51.Kg6 e5 52.dxe5+ (not 52.fxe5+ fxe5 53.dxe5+ Kxe5 54.b5 axb5 55.axb5 Kd6 56.Kf5 Kc5 57.Ke5 d4 58.Ke4=) 52...fxe5 53.f5 e4 54.f6 e3 55.f7 e2 56.f8£+)  

51.Kg6 

 

51...e5! 
Black must avoid putting his king on e7 because after 51...Ke7 52.f5 (52.b5 axb5 53.a5 Kd6 54.Kxf6 b4–+) 52...exf5 (52...e5 53.dxe5 fxe5 54.Kg7  the rule of controlling your passed pawn queening square. White will queen first and stops the passed black pawns.) 

 53.Kxf5 Kf7 54.b5 the principle of further outside passed pawn winning 54...axb5 55.axb5 Ke7 56.b6 Kd6 57.Kxf6 Kc6 58.Ke6 Kxb6 59.Kxd5 Kc7 60.Ke6 Kd8 61.Kd6 the rule is that if the winning side king reaches the sixth rank in front of his passed pawn, the position is always won. 61...Ke8 62.Kc7 Ke7 63.d5) 

52.dxe5 fxe5 53.f5 

53.fxe5 is also drawn 53...Ke6 54. b5 axb5 55. axb5 Kxe5 56. b6 Kd6 57. Kf5 Kc6 58.Ke5

e4 54.f6 e3 55.f7 e2 56.f8Q e1Q  

Despite queening first, white cannot exploit the situation 

57.Qf7+ Kd6 58.Qf8+ Kd7=

Replay this variation below

The second plan is to use the potential passed pawn to zugzwang black and force him to retreat.

43.Ka3!! We always learn to move our king to the centre in endings so this move is illogical and hard to see. It's all about tempo moves now.

43...Kb6 44.a5+! 

Another difficult move to see, much less play. Our minds are trained from bitter experience not to push pawns in such a way that the opposing king can blockade them. But here it is the correct way to win.

Kb5 45.Kb3 Kc6 

 [45...f6 46.g3 zugzwang 46...e5 47.fxe5 fxe5 48.dxe5 d4 49.e6 Kc6 50.Kc4 Kd6 51.b5! axb5+ 52.Kxd4+– 

Black cannot capture on e6 as he will be outside the square of the passed pawn.

46.Ka4 f6 47.g3 

Black is in zugzwang again  47...Kc7 48. b5 axb5 49. Kxb5 is a typical outside passed pawn win.

47...e5 48.fxe5 fxe5 49.dxe5 d4 50.Kb3 Kd5 

This looks promising for black but now white plays

51.b5!  axb5

the principle of two distant passed pawn (a-pawn and e-pawn) versus less distant for black (b-pawn and d-pawn). The white king can stop both pawns whereas the same cannot be said for black 

 52.a6 Kc6 53.e6+–

Replay this variation below

So Li Tian prematurely agreed the draw and maybe missed the chance to beat another grandmaster. If he did would he still win the last game and achieve that first IM norm? We will never know the answer. But take heed the words of GM Le Quang Liem when he said of one of his games - "missing a chance to win is also a precious lesson for me. It reminds me to look back and exert more effort, in order not to repeat such mistakes in the future." Read his full blog entry here