Promotion
Besides threatening the king, checkmate, stalemate, and capturing pieces or pawns, a very dangerous threat is that of pawn promotion. This one is perhaps a little more sophisticated than you might think. The threat of promotion does not only refer to a pawn on the seventh or second rank poised for the coming coronation. It also refers to any passed pawn that is not properly restrained.
Pawn Majority
We have already met the pawn majority in the last chapter. So we know that a pawn majority is more pawns of one color than of the other color on one side of the board. The strength of such a majority is that after the pawns are traded off, one for another, a lone pawn will emerge. That will be a passed pawn, which means it is a pawn that will eventually threaten to promote.
Pawn majorities, and especially passed pawns, are particularly strong in the endgame, when most of the pieces have been exchanged off and are gone. In such cases, the kings become strong pieces, and can help a pawn to promote or help stop a pawn from promoting.
Candidate
The way to use a pawn majority is to move up the candidate passed pawn first. The candidate is the one with no enemy pawns on the same file.
The entire pawn majority continues to advance up the board, with the candidate leading the way. The b-pawn is the candidate. 1. b5 Kg6 2. a5 Kf6 3. b6 axb6 4. axb6 Ke6 5. b7 Kd6 6. b8=Q.
Outside Passed Pawn
This is a special case that often comes out of an outside pawn majority. The “outside” refers to the side of the board away from the kings. So if the kings are busy on the kingside, a pawn majority on the queenside will produce an outside or distant passed pawn. The way to use such a pawn is to march it forward, forcing the enemy king to come over to stop it. Then your own king can mop up the pawns the enemy king was forced to abandon.
1. b5 Ke6 2. a5 Kd6 3. b6 axb6 4. axb6 Kc6 5. b7 Kxb7 6. Kf5 and the White king dines on Black's pawns.
Combinations
Here are some combinations in which a passed pawn is created and/or promotes.
Keep in mind the pawn's ability to underpromote. Probably 99 percent of the time an underpromotion will not be a real threat. But every once in a while a knight or a rook could destroy your position, while a queen won't make much difference. Take each position on its own merit.
Black to move plays 1…. a3 and keeps marching the pawn to a1.
White plays 1. Kc5 and mops up the queenside pawns. There is no need to push his passed pawn: The Black king will have to keep a sharp eye on it, so it won't be able to do any damage.
White breaks through with 1. b6! axb6 2. c6! bxc6 3. a6 and the a-pawn marches through. Or 1. b6! cxb6 2. a6! bxa6 3. c6 and the c-pawn marches through.
Even though there are a few pieces left, the threat of promoting a pawn makes the following combination possible.
Black to move wins with 1…. h3! And there is no way to stop one of the Black pawns from safely promoting.
