Pawn Promotion Chess Rule: When Not to Take a Queen

Here is our guide to pawn promotion in chess. If you are just starting out, this article is for you.

Here's what this guide covers.

• The rule itself.
• An important trick called underpromotion.
• What promotion means for your overall strategy.

Knowing how the pawn moves in chess is obviously important before going any further.

The Pawn Promotion Rule

Pawn promotion is easily the most fun rule in the whole game.

When a pawn reaches the last rank, the far side of the board from where it started, it must turn into another piece of its own color, chosen by the player. It can become a queen, a rook, a bishop, or a knight, but never a king, and it can never simply stay a pawn.

You are not limited to pieces that have already been captured either. It is entirely legal to end up with two, three, or even more queens on the board at once. So one perfectly good plan in chess is to push a pawn all the way down the board and win material.

Here are a few tips and tricks that follow from this important rule.

Before we go further, if you are still building the basics, our guide on how to play chess covers the fundamentals and gives you exercises to practice on.

Underpromotion: Don't Always Choose a Queen

There are rare cases where it is actually better to promote a pawn to a piece other than the queen. This is what chess players call underpromotion.

Here are two examples. In both, it is White to move.

Here is the first example. White to move and win.

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The trap here is that if White promotes the f-pawn to a queen (f8=Q), the black king is stalemated. It cannot move, but it is not in check either, so the game is an immediate draw. The queen on f8 controls the h6 square along the diagonal, which is the one escape the black king had.

The right move is to promote this pawn to a rook instead, 1.f8=R. Black's only move is then 1...Kh6, and 2.Rh8# is mate.

Here is a second example. Again, White to move and win.

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In this position, if White turns the f-pawn into a queen (f8=Q), the game stays balanced. But if White instead promotes it to a knight (f8=N), the new knight forks the black king and queen with check, so Black has to move the king and White picks up the queen.

In both of these examples, White played what chess players call an underpromotion. It is a small idea, but it is one of the sharpest tricks the promotion rule has to offer.

A One-Pawn Edge Can Be Enough to Win

This is another consequence of the promotion rule. Having just one extra pawn can often turn into a pawn majority on one side of the board, and that majority can be enough to push a pawn all the way to promotion. That is exactly why a single extra pawn is so often the difference between a win and a draw at a high level.

Let's look at an example.

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White only has one extra pawn, and yet this position is winning for White.

Let's take a moment to understand why. You can think of White's extra pawn as the one sitting on a2. As it advances, it will force the black king to run over and stop it. If Black ignores it, that pawn will queen on its own. Once the black king is tied down near the a-pawn, the white king is free to march over to the other side of the board and start collecting Black's pawns there. The funny part is that the pawn which finally queens will be one of White's f-, g- or h-pawns. And it only works because the a-pawn gets sacrificed along the way.

Pawn Promotion in Chess Puzzles

We will finish this article with a small puzzle for you to work through.

White to move, mate in two.

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The Solution

The trap is that promoting to a queen leads to stalemate, which is only a draw.

So the answer has to be an underpromotion. 1.e8=R is stalemate too, and 1.e8=N does not mate either, because Black simply steps to g8 or h8.

The right move is 1.e8=B!!

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After 1...Kg8 or 1...Kh8, 2.Bxg6# is a discovered checkmate.

A nice finish, isn't it?

Your Move

That was our guide to pawn promotion in chess. To keep going, here are a few good next steps.

• Keep learning the fundamentals with our guide on how to play chess.
• Discover the full set of chess rules, including castling, stalemate, and en passant.
• Browse more chess lessons on our blog.