Tim Harding's, Winning at Correspondence Chess (Batsford, pounds 14.99) is a well-researched account of one of the more arcane sides of the game. It may, however, turn out to be an obituary for a mode of play that is rapidly becoming obsolete through the spread of computers, fax machines and e-mail.

The idea of playing by post has always attracted a curious type of chess player. Patient beyond belief, they are quite content, in international contests, to spend a year or more in winning a delicate endgame, at the rate of a move every three or four weeks. And to suffer the ordeal of losing such a game is a risk to which most players would not willingly subject themselves.

The general level of strategy in postal games is below the standard of the best over-the-board players, yet it is undeniable that the sheer volume of calculation possible in this form of chess enables tactics to be lifted to a level of perfection unknown in real life.

As Harding's book shows, many opening innovations have also first seen the light of day on emerging from the envelope of a correspondence player. Here's an example:

White: Tronhjem

Black: Christensen

Danish Corres. Champ. 1994

1 e4 e5 9 Re1 Nxf2

2 Nf3 Nf6 10 Bxh7 Ne5

3 d4 Nxe4 11 Rxe5 Be6

4 Bd3 d5 12 Bg8 Qh4

5 Nxe5 Nd7 13 Ng6 Qxd4+

6 Nxf7 Qe7 14 Ke2 Bd6

7 Nxh8 Nc3+ White resigned

8 Kd2 Nxd1

The whole variation, up to 10.Bxh7, had occurred in a game between Igor Zaitsev and Karpov in 1966, which was quickly drawn after 10...Ne4+ 11.Rxe4! dxe4 12.Bg6+ Kd8 13.Nf7+ Ke8 14.Nd6+ Kd8. Two later grandmaster games also copied those moves, accepting Zaitsev's comment that 10...Ne5 11.Rxe5 Be6 was "very risky" for Black. Christensen proved them all wrong, though Harding takes great glee in describing how, in his own game against Christensen, he won with the move 7.Qe2! instead of Nxh8.

Anyone interested in playing chess slowly may contact the British Postal chess Federation at 173 Gaddesden Crescent, Wavendon Gate, Milton Keynes MK7 7SF or surf the open seas of the internet with the International E- Mail Chess Group (iecg@ cc.UManitoba.ca).