by IM Larry Kaufman
Nearly every beginner soon hears that doubled pawns are bad, and some even interpret this to mean that a piece should not be recaptured if it leads to doubled pawns! On the other hand, many grandmasters often seem to play as if the doubling of pawns is a desirable goal. It is the goal of this article to clarify this contradiction and explore the different types of doubled pawns.
Long-time readers of this magazine may recall that in 1999, I ran an article in which the average values of the pieces under differing circumstances were explored using database statistics. I have again made some use of this same method for this article, although software limitations only allow me to confirm a few of the statements made here. Again, I am using a database (now of about 600,000) games in which both players are of at least FIDE Master standard (2300+), and I require that whatever situation is being tested to remain on the board for three full moves. Results are analyzed by performance rating minus actual rating rather than by raw scores, and are expressed as a fraction of a pawn. All opening statistics are based on the “PowerBook 2005” database of about a million games.
The first statement I can confirm is that doubled pawns are indeed on average undesirable, by about 1/8 of a pawn. However this statistic needs to be broken down to be useful. Doubled pawns themselves are really more serious than this generally, but when your pawns are doubled you automatically get an extra half-open file for your rooks (or queen, but the queen can also use diagonals). So it follows logically that the net cost of doubled pawns is much greater in the absence of major pieces. The database shows that with all rooks present, doubled pawns only “cost” about 1/16 of a pawn on average. With one rook each, the cost rises to ¼ pawn, and with no rooks present to 3/8 of a pawn. With the queens present, the cost is again only 1/16 of a pawn; without them it’s a quarter pawn. So the lessons are clear; beware of doubled pawns when major pieces have been exchanged, and beware of exchanging major pieces when you are the one with the doubled pawns.
The next point about doubled pawns is that they arise only by captures. Since players generally capture towards the center when given a choice, the doubling of pawns tends on average to increase central control. However the database shows that the difference in value between pawns on different files is quite small, with the exception of the edge pawns, which are on average worth about 0.85 pawns. This means that a capture by an edge pawn that produces doubled pawns is on average a slightly favorable transaction. With all the major pieces still present, it is a clearly favorable one, and with a rook still on the newly opened file it is generally highly desirable. This explains why there are so many openings in which each player hopes to induce the opponent to exchange pieces on the b3, b6, g3, or g6 squares. But note that if most of the major pieces have been exchanged, even the doubling of pawns by an edge pawn capture is generally undesirable.
Why are doubled pawns bad? There are two main reasons. First of all they are in general a bit weak, because they cannot defend each other and because the front one cannot usually be defended from behind by a rook or queen. This is most apparent in the case of doubled isolated pawns, which are generally considered pretty bad, especially if they are on a half-open file where they are subject to attack by an enemy rook or queen. In general, doubled isolated pawns on a half-open file are worth only slightly more on average than one healthy pawn. Thus, in the Open Sicilian whenever Black can play the sequence …Rxc3 bxc3 Nxe4 he should usually do so, since one pawn plus the severely damaged pawn structure is worth at least the Exchange (par value 1 ¾ pawns).
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