Chess Openings Lab
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Pirc Defense: Byrne Variation

The Byrne Variation is 4.Bg5 in the Pirc, where White develops the bishop to g5 before deciding where the knight on g1 goes. White plans Qd2, long castling and sometimes Bh6, while Black asks the bishop a question with ...h6 and plays for queenside counterplay.

Moves
1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.Bg5
ECO
B07
Engine
+0.56 · a slight edge for White (Stockfish 17.1, depth 20)
Played
2,276 games in our lichess sample
White scores
53.9%

Key ideas for both sides

White

  • Follow with Qd2 and O-O-O, aiming for an attack with Bh6 or a pawn push on the kingside.
  • Answer ...h6 by retreating Bf4 or Be3, keeping the bishop on a good diagonal.
  • Against ...c6 and ...b5, play a3 to keep the knight on c3 stable.
  • Develop the g1 knight to f3 after the queen is out.

Black

  • Play ...h6 to ask the bishop where it is going.
  • Use ...c6 and ...b5, as in the second engine line, to gain queenside space.
  • Develop with ...Bg7, ...Nc6 and ...a6, then play ...b5 against a long-castled king.
  • Strike with ...e5 when the bishop has left g5.

Plans and pawn structure

The structure is the classical Pirc center: e4 and d4 against d6 and g6. White plays Bg5, Qd2 and O-O-O, then Bh6 or a kingside pawn push. Black plays ...h6, ...c6 and ...b5, or ...Nc6 and ...a6, and counters on the queenside. The ...e5 break is Black's main central idea when White's bishop leaves g5.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.56: a slight edge for White. Its three top choices for Black:

  1. +0.56 4...Bg7 5.Qd2 h6 6.Bf4 Nc6 7.O-O-O
  2. +0.59 4...c6 5.Qd2 Nbd7 6.Nf3 Qc7 7.Bh6
  3. +0.67 4...h6 5.Be3 e5 6.h3 Nbd7 7.Nf3

Pawns, from White's side.

How it scores on lichess

2,276 rated lichess games reached this position; White scored 53.9%.

under 120053.2%
1200–159952.5%
1600–199952.5%
2000 and up59.3%

Light: White wins. Grey: draws. Dark: Black wins. About the sample.

How to play against it

As Black, play ...h6 to question the bishop, then ...c6 and ...b5. Do not castle short too early into White's attack. Use ...e5 when White's pieces are committed.

Questions

What are the moves of the Pirc Defense: Byrne Variation?

The Pirc Defense: Byrne Variation starts 1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.Bg5. Its ECO code is B07.

Is the Pirc Defense: Byrne Variation good for White?

Stockfish 17.1 rates the position +0.56 at depth 20, which is a slight edge for White. In 2,276 lichess games from our sample, White scored 53.9%. A flexible attacking choice for White, while Black needs good timing for ...h6 and the queenside push.

What is the main idea of the Pirc Defense: Byrne Variation?

White develops the bishop to g5, then plays Qd2 and long castling. Black asks the bishop with ...h6 and counters with ...c6 and ...b5.

What should Black play next?

The engine's first choice is Bg7, with c6 and h6 close behind. 4...Bg7 develops and keeps ...h6 for later.

Updated October 2026. Sources and method.