Sokolsky Opening

The Sokolsky Opening (also known as the Orangutan or Polish) is an uncommon chess opening that begins with the move:
According to various databases, out of the twenty possible first moves from White, the move 1.b4 ranks ninth in popularity. It is considered an irregular opening, so it is classified under the A00 code in the "Encyclopaedia of Chess Openings" ("ECO").
Details.
The opening has never been popular at the top level, though a number of prominent players have employed it on occasion (for example, Richard Réti against Abraham Speijer in Scheveningen 1923 and Boris Spassky against Vasily Smyslov in the 1960 Moscow–Leningrad match). Soviet player Alexei Pavlovich Sokolsky (1908–1969) wrote a monograph on this opening in 1963, "Debyut 1 b2–b4".
Perhaps its most famous use came in the game Tartakower versus Maróczy, in the New York 1924 chess tournament on March 21, 1924. The name "Orangutan Opening" originates from that game: the players visited the Bronx Zoo the previous day, where Tartakower consulted an orangutan named Susan, and she somehow indicated, Tartakower insisted, that he should open with b4. Also, Tartakower noted that the climbing movement of the pawn to b5 reminded him of the orangutan. In that particular game, Tartakower came out of the opening with a decent position, but the game was drawn. Alekhine, who played in the tournament and wrote a book on it, said that 1.b4 was an old move, and that the problem is that it reveals White's intentions, before White knows what Black's intentions are.
The opening is largely based upon tactics on the or the f6- and g7-squares. Black can respond in a variety of ways: For example, Black can make a claim on the (which White's first move ignores) with 1...d5 (possibly followed by 2.Bb2 Qd6, attacking b4 and supporting ...e7–e5), 1...e5 or 1...f5. Less ambitious moves like 1...Nf6, 1...c6 (called the Outflank Variation, preparing ...Qb6 or ...a5), and 1...e6 are also reasonable. Rarer attempts have been made with 1...a5 or 1...c5. Black's reply 1...e6 is usually followed by ...d5, ...Nf6 and an eventual ...c5. After 1.b4 e5 it is normal for White to ignore the attack on the b-pawn and play 2.Bb2, when 2...d6, 2...f6, and 2...Bxb4 are all playable. After 1...a5 White will most likely play 2.b5 and take advantage of Black's queenside weakness. Black's 1...c5 is much sharper and more aggressive and is normally used to avoid theory. After the capture Black will generally place pressure on the c5-square and will develop an attack against White's weak queenside structure at the cost of an inferior central position.
References.
Bibliography