Hansen challenged me out of the blue, asked me to show him some 'tricks.' I was happy to oblige.

This initiates the Panov-Botvinnik Attack variation of the Caro-Kann; it tends to produce sharp attacking games.

This is an 'innovation' not given in any opening book I am familiar with; we're both flying by the seats of our pants from here on.

Black trades off his bad bishop.

Black keeps his good bishop.

This is a strategic error; although it blocks Black's bishop, it commits the one cardinal sin of the Panov-Botvinnik: Black must not play timidly in the P-B, he must attack. The text move, however, reduces tension on the queen-side and thus allows Black to mount a king-side attack instead.

Given that White has a static queen-side and there is no danger of a breakthrough there, Black immediately prepares to advance pawns on the king-side.

d4xe5? Nxe5; Qd4, Bxc5! and the queen cannot take the bishop on account of the knight fork on d3+. Neither can the queen take the knight on e5, as the queen would be skewered against the king after . . . Re8.

White is in deep trouble; Black has seized the initiative and control of the centre.

This exerts a serious cramp upon White's position.