ECO C67 · Ruy Lopez
Ruy Lopez: Berlin Defense, Rio Gambit Accepted
The position after 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6 4.O-O Nxe4.
1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O Nxe4
Ruy Lopez: Berlin Defense, Rio Gambit Accepted is filed under ECO C67, a variation of Ruy Lopez: Berlin Defense. It is the position after 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6 4.O-O Nxe4 — 8 half-moves in, with White to move. Named theory ends here; beyond this the position is yours to work out.