The Agincourt Defense, Catalan Defense is a variation of the English Opening, catalogued as ECO A13. The line runs 1. c4 e6 2. Nf3 d5 3. g3 b6 4. Bg2 Bb7 5. O-O, reaching the position shown below after 9 half-moves.
Black holds the centre with pawns on d5, and one pawn capture is available, so the structure has not settled yet. Development is level at two minor pieces each. It is Black to move after five moves. White has castled while Black’s king is still uncommitted.
On the English Opening generally: A flexible opening where White controls the center with c4. Can transpose into many different systems.
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The Agincourt Defense, Catalan Defense goes 1. c4 e6 2. Nf3 d5 3. g3 b6 4. Bg2 Bb7 5. O-O. It is a variation of the English Opening and is catalogued as ECO A13.
The Agincourt Defense, Catalan Defense is ECO A13. ECO codes group openings by their move order, so nearby codes cover closely related lines of the English Opening.
Stockfish evaluates the position after 1. c4 e6 2. Nf3 d5 3. g3 b6 4. Bg2 Bb7 5. O-O at +0.17 at depth 18, which is balanced. Engine evaluation is only a starting point — at club level the practical value of a line is mostly about whether you know its plans better than your opponent does.
Black holds the centre with pawns on d5, and one pawn capture is available, so the structure has not settled yet. Development is level at two minor pieces each. It is Black to move. White has castled while Black’s king is still uncommitted.