Chess Opening Theory/1. f4/1...d5

=Bird's Opening=

1...d5
From here, one possible reply is to treat the position as a Dutch Defence reversed. As in the Dutch, white can either fianchetto with 2. g3 (Leningrad Dutch) or go for the Stonewall with 2. e3, soon followed by d4 and c3.

Another possible motive is to go with a uniquely "Bird" strategy of dark-square control. The plan is to develop the King's knight to f3, to fianchetto the dark-square bishop with b3 and Bb2, and to focus in further pressure on the e5 square, sometimes with Qe1 and Qg3. Depending on the position, the white-squared bishop can go either on e2 or on b5 (with the idea to exchange it for the black knight on c6 and clear the way for the move Nf3-e5). The main problem with the arising positions is where to put the b1 knight. Sometimes c3 or d2 are good squares, but at other times, (especially if black pushes d5, c5, d4), it may be good to play a4 and put the knight on a3, with increased queenside control and flexible options.

A third strategy is simply to play for the break e4. The logical moves are d3, Nd2, and Qe1. Note that the king's bishop will go to e2 if black plays Bg4.

Theory table

 * 1.f4 d5