What is the Bird opening (with differents variations)
The Bird opening (or early Bird) is an irregular chess opening characterized by the move 1.f4. It is named after the 19th century British master Henry Edward Bird (Portsea, July 14, 1830 - April 11, 1908).
According to ChessBase, for the masters, 1.f4 is the seventh move in popularity. It is much less popular than the symmetrical flank opening 1.c4 (the English opening) mainly because 1.f4 weakens the white king wing somewhat. One of the rare great masters to have used it regularly is the Dane Bent Larsen. 1.f4 is also common at GMI Henrik Danielsen parties.
Note that at an amateur level, this opening is an effective weapon and allows to obtain a certain number of gains due to the ignorance of the lines (rare are the club players who master the different variants…).
Sometimes White advances the c-pawn in order to surprise their opponent: it is the gambit Sturm - Mujannah which is a surprise and an aggressive reaction forcing Black to make an unexpected decision in the main variant of the Bird 1.f4 opening. d5: indeed White immediately offers a pawn on the queen-wing 2.c4. Black must make the decision to accept or reject this gambit.
The Mujannah-Sturm gambit (2.c4)
This Sturm - Mujannah gambit should be handled with care, because if Black is playing solid it does not lead to a serious advantage or even an unfavorable position. A priori, Black obtains better positions if they refuse this gambit and respond, for example, with moves such as 2 ... d4, 2 ... e6 or 2 ... Nc6. This gambit has an underdeveloped theory: it can therefore represent an interesting weapon in blitz.
Inverted Leningrad structure, polar bear system
Regarding the reverse Dutch variant, GMI Henrik Danielsen has refined a variant called the Polar Bear System.
Some general concepts are set out below:
1.f4 d5 2.Nf3 g6 3.g3 Bg7 4.Bg2 Nf6 5.O-O O-O 6.d3 c5 7.c3 Nc6 8.Ca3 (fundamental position)
Classic developments
Let's go back to the classic scheme where the game generally takes on the appearance of a Dutch defense (1.d4 f5) with the colors reversed. The Whites will then:
either place the mad king in fianchetto with Cf3, g3, Bg2 and O-O with a structure similar to the Dutch Leningrad variant inverted;
either adopt a Stonewall formation with pawns at d4, e3 and f4 and attempt a king wing attack;
or even place their mad queen in fianchetto to increase the hold on the e5 square.
Another strategy, by analogy with the Iline-Jenevski variant of the Dutch defense, is for White to play e3, Fe2, OO, d3 and try to achieve the e3-e4 breakthrough in various ways, e.g. Ce5, Bf3, De2 and finally e3-e4 or simply Cc3 followed by e4.