C41White2 book lines continue
Philidor Countergambit, del Rio Attack
Philidor Defense1. e4 e5 2. Nf3 d6 3. d4 f5 4. dxe5 fxe4 5. Ng5 d5 6. e6
Also known as Philidor: Philidor Countergambit, del Rio Attack, Philidor: Philidor counter-gambit, del Rio attack.