Pirc Defense, 150 Attack

The 150 Attack is usually recognized after 1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.Be3, with a representative line continuing 4...c6 5.Qd2. White places the bishop on e3 and queen on d2 to coordinate several ideas: exchanging Black's g7-bishop with Bh6, preparing long castling, the special move that places White's king on c1 and rook on d1, and advancing the h- or g-pawn.

The sequence is written in algebraic notation: squares such as e4 combine a column letter and row number; N means knight, B bishop, R rook, and Q queen; pawn moves normally show their destination, x marks a capture, and + marks check. Moves are read in pairs, White first and Black second; dots before a move shown alone indicate Black's turn.

If Black castles short, placing the king on g8 and rook on f8, the kings stand on opposite sides of the board. Each side can then advance pawns toward the opposing king without immediately removing its own king's pawn cover, so the attacking race can become very fast.

The plan is not automatic

• White wants to bring the remaining pieces out, choose the right moment for Bh6, use f3 to support g4, and open lines with h4-h5 before Black opens paths toward the king that usually stands on c1 after long castling.
• Black can attack the e3-bishop with ...Ng4, prepare ...c6 and ...b5 against White's king, or strike the center with ...e5.

The 150 Attack is a system, a recognizable piece setup that may be reached through several move orders, rather than a forced sequence. The correct order depends on Black's response, and long castling can be dangerous if ...b5 is already advanced. It differs from the Austrian Attack, which begins with 4.f4 and first builds a broad central pawn front.