Polish Opening

The Polish Opening, also called the Orangutan Opening, begins 1. b4 and is classified under A00 among the irregular openings. Rather than occupying the center at once, White claims space on the queenside and prepares Bb2, placing the bishop on the long a1-h8 diagonal. Central pawn advances follow only once that bishop is developed. The b-pawn also carries ideas of its own: b4-b5 can drive a knight away from c6, and trading it for Black's c-pawn can leave White with extra central pawns. The usual objection is that b4 can often be played later, so spending the first move on it leaves Black free to choose a setup. This helps explain its rarity in modern practice, although Tartakower and Magnus Carlsen have both won with it in tournament play.

Because the pawn on b4 is unprotected, the most frequent reply, 1...e5, both takes the center and opens the f8-bishop's diagonal toward it. White chooses between 2. a3, the Bugayev Attack, which defends the pawn, and 2. Bb2, which strikes at e5. After 1. b4 e5 2. Bb2 Black can capture with 2...Bxb4 3. Bxe5, conceding a central pawn majority in exchange for a small lead in development, with chances close to level. Quieter is 2...d6, the Czech Defense, while 2...f6 3. b5 is the Bugayev Advance Variation. Against 1...e6 the same capture is a blunder, since 1. b4 e6 2. Bb2 Bxb4?? 3. Bxg7 wins a rook.

Advancing to b5 to avoid harassment is a recurring theme, as in the Schiffler-Sokolsky Variation, 1. b4 e6 2. Bb2 Nf6 3. b5 d5 4. e3. The push secures queenside space, but the pawn becomes exposed and can be hard to maintain. The second most popular reply is 1...d5, after which 2. Bb2 Bf5 is the Baltic Defense. In the King's Indian Variation, 1. b4 Nf6 2. Bb2 g6, Black opposes the b2-bishop with a fianchetto of his own. Rarer tries include 1...c6, the Outflank Variation; 1...c5, the Birmingham Gambit, offering the c-pawn; 1...f5, the Dutch Defense; 1...b5, the Symmetrical Variation; and 1...Nc6, the Grigorian Variation, which attacks b4 immediately.

In online play the opening appears frequently for an irregular first move, ranking around a hundredth among named openings by games played. White scores somewhat better than Black there, and draws are uncommon. Engine assessment puts the position after 1. b4 as roughly balanced with a faint lean toward Black, and the main lines generally lead to equal positions in which understanding of the resulting structures matters more than memorized theory.