Last week, we looked at the passed pawn in general. Promoting a passed pawn usually ends the game in favour of the promoter as it creates huge material imbalance if the pawn becomes a queen. But this is not always the case!
Sometimes underpromotion is necessary in order to checkmate the opponent king and to meet opponent’s resources such as counter promotion, checkmate threats, the threat of capturing the promoted piece and drawing tricks. Here are some enlightening examples:
1) Robert Fontaine against Maxime Vachier Lagrave in 2007:
Underpromotion to meet perpetual checks and checkmating the opponent king
Q: How would you proceed with Black pieces?
A: Black can checkmate the opponent king with series of forcing moves using underpromotion.
This is the only way to pocket the point, promoting the pawn into a queen leads only to a draw after Qxc7.
2.Kf4 Rh4+ 3.Kg5 Be3+!
Sacrificing the rook.
White resigned in view of 6. Kg6 g4#.
2) Aron G Reshko against Oleg Kaminsky in 1972:
Underpromotion to avoid stalemate tricks
Q: What would you promote to on a8?
A: Promoting to a queen or rook fails to Qf7+!! due to stalemate tricks. In the game White promoted the pawn into a bishop and went on win after couple of moves.
3) Nakamura against Kramnik in 2012:
Underpromotion leaves Black without any counter chances.
Q: How would you proceed with the White pieces?
A: In the game White played 1.c8=N+, the only move to win the game because promoting pawn into queen can be met by exd1=Q+ whilst 1.Kxe2 can be met by f3+ followed by Bxc7. Black tried hard for next 18 moves but failed to save the day. Here are rest of the moves in case you’re interested.
62…Kf6 63.Kxe2 Ke5 64.Nb6 Kd4 65.Bg2 Be1 66.Nd5 Ke5 67.Nb4 Bh4 68.Nd3+ Kf5 69.Kxd2 Kg4 70.Ke2 Bf6 71.N1f2+ Kg3 72.Bf3 Bd8 73.Ne4+ Kh4 74.Ne5 Bc7 75.Ng6+ Kh3 76.Ne7 Bd8 77.Nf5 Bb6 78.Kf1 Kh2 79.Bg4 f3 80.Nh4 1–0