Promotion (chess) - Promotion To Various Pieces

Promotion To Various Pieces

Promotion to a queen is the most common in practical play, since the queen is the most powerful piece. Underpromotion (promoting to a piece other than a queen) occurs more often in chess problems than in practical play. In practical play, underpromotions are rare, but not extraordinarily so (see table below). As the most powerful piece, the queen is usually the most desirable, but promotion to a different piece can be advantageous in certain situations. A promotion to knight is occasionally useful, particularly if it occurs with check. A promotion to a rook is, on rare occasions, necessary in order to avoid a draw because of an immediate stalemate that would occur if the promotion was to a queen. Promotion to a bishop almost never occurs in practical play (about one game in 33,000). (See Underpromotion: Promotion to rook or bishop for examples of underpromotions to rook and bishop made in order to avoid stalemate.)

The percentage of games involving promotions can be misleading because often a player resigns when he sees that he cannot stop his opponent from promoting a pawn. In the 2006 ChessBase database of 3,200,000 games (many grandmaster- and master-level), about 1.5 percent of the games contain a promotion. In these games (counting games in which multiple promotions by the same player to the same piece occur only once), the fraction of times each piece was promoted to is approximately:

Fischer vs. Petrosian, 1959

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

Position after 37. h8(Q), four queens

Piece	Percentage
Queen	96.9
Knight	1.8
Rook	1.1
Bishop	0.2

This suggests that about 3 percent of all promotions are underpromotions. The frequency of truly significant underpromotions is, however, less than this. Note that the promotion is not limited to pieces that have been captured. A player may promote to any piece they wish, regardless of whether or not it has been taken. In theory, a player could have nine queens, ten knights, ten bishops or ten rooks, though this is an improbable scenario. Some chess sets (see Chess piece) come with an extra queen of each color to use for promoted pawns. If an extra queen is unavailable, it is often represented by an inverted rook instead.

The diagram from the game between Bobby Fischer and Tigran Petrosian in the 1959 Candidates Tournament shows a position in which each side has two queens. Four queens existed from move 37 until move 44 (Fischer 2008:113–14).