C41 Philidor Defence

ECO code C41 covers the Philidor Defence, 1.e4 e5 2.Nf3 d6, where Black supports the e5-pawn with a pawn rather than a knight. White usually strikes at once with 3.d4. After 3...exd4 Black gives up the centre and develops behind a compact pawn on d6, aiming for ...Be7, ...0-0 and later ...Re8 or ...d5. The Hanham and Lion set-ups keep the pawn on e5 with ...Nf6 and ...Nbd7, often reached by 1...d6, 2...Nf6 and 3...e5. That structure is solid but cramped, and Black frees it later with ...c6 and ...b5. Against it White can trade queens with dxe5, leaving Black's king on d8.