Continuing our series on the technique of exploiting an extra pawn, we move along to a different kind of situation compared to our example from last week (Gligoric-Smyslov). In last week's example, we saw Smyslov, with an extra - although somewhat devalued - pawn, in a fairly calm situation, needing only to find a plan of making progress. This week we see Alexander Alekhine, in his 1927 World Championship match with Jose Raul Capablanca, holding an extra pawn but with an over-extended position and facing some significant counterplay.
This position is much more concrete than Smyslov's game against Gligoric. While Alekhine has a healthy extra pawn and the better structure (the d5 pawn is isolated, and White could also create a passed pawn easily by f3 and e4), he faces serious counterplay on the c-file, on which he cannot prevent the black rook from invading. Were the white king on d3, Black would be justified in resigning - but as it is, White's winning chances depend on exact variations, in which he tries to turn his extra pawn to account, mostly by returning it to regain control of the position. What resulted was a complex, colorful ending where Alekhine's win hung by a thread.
The game began as follows (I will not annotate the beginning of the game, which does not fall inside our theme, but notes can be found in Alekhine's collection of his best games, My Best Games of Chess, 1924-1937, and probably elsewhere as well):
In order to avert the threat of White's kingside attack, Capablanca felt compelled to go into this pawn-down ending. Although being a full - healthy - pawn down, the Cuban secured a very important source of counterplay - control of an open file, leading to a rook invasion on the seventh rank.
If you saw part one of the "A Pawn Up" series, you may have noticed that Gligoric began with control of the d-file. However, in that case White was unable to use the open file for any kind of invasion, while here Black is assured of getting a rook to permanently occupy the seventh rank. This is the all-important difference.
Nevertheless, you can easily surmise that White has the better position despite this - mainly because he is able to choose the most appropriate moment to relinquish his extra pawn, making Black's active rook less meaningful, and meanwhile gain advantages elsewhere on the board.
To begin with, Alekhine exchanges a pair of rooks. This was done not just to make Black's occupation of the seventh rank less dangerous (there would later be no chance of doubled black rooks on the seventh), but most importantly to make sure that the black position would be exposed after White finally decides to relinquish his b-pawn and use his own rook actively. He also needs to prevent the black king from invading on the light squares, and prepare his own plan of later creating a passed pawn with f3 and e4.
Although Alekhine's play was not perfect (32.a6 appears to be much better than the 32.Rc1 of the game, and Black probably should have drawn with correct play in the game), much can be learned from this ending. Front and center is the concept of conversion of advantages. This is one of the great plusses that an extra pawn can convey, and a major method in utilizing the extra pawn - returning the pawn in order to gain some more easily exploitable positional advantage. We saw this in the above game at various points - when Alekhine played 24.Rhc1, 32.Rc1 (although 32.a6 was probably a better way of carrying out the same idea), and later with 50.h5 and 54.Kf5.
Other important concepts are that activity is paramount in endings with rooks. In many variations above we see either player sacrificing material or structure for the purposes of activating their rooks or king. A player should internalize such concepts as the king being cut off on the first rank. You should almost be able to feel the pain of Alekhine's king around move 46, cut off on the first rank and unable to take part in the struggle, and its great relief at being able to go to g2 on move 48. A further very important concept, which can be seen near the end of the game and also in several variations throughout, is the great value of centralization in rook and pawn endings. While in king and pawn endings, an outside passed pawn is usually a major advantage, in rook and pawn endings the central passed pawn, supported by a king (even if opposed by the other king) is quite often far more important. This can clearly be seen in the variation starting with 32.a6.