rules, tactics, strategies and history

Black's Response to King's Pawn Openings: Variation I

(3) Qxd4 Kt-c6
(4) Q-e3

Now P-d5 is not possible because of Pxd5 check.

(4) ... Kt-f6
(5) Kt-c3 B-e7
(6) B-d2 P-d5

Threatening to win a piece by P-d4.

(7) Pxd5 Ktxd5

Now White has no center-Pawn either; Black has a perfectly good game.