Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...a6/4. Ba4/4...Nf6/5. O-O/5...Nxe4/6. d4/6...exd4/7. Re1/7...d5/8. c4

=Ruy Lopez:Riga Variation=

White has just advanced his c pawn into the center, threatening to pull one of Black's d pawns away.

Black can choose to take the pawn with either the d5 or d4 pawn, or ignore White's threat of cxd5, which intends to remove the defender from the pinned e4 knight.

If Black chooses to take en passant with 8...dxc3, White can respond Nxc3, putting another attacker on the pinned e4 knight.

The response 8...Bb4 9.cxd5 Bxe1 10.Qxe1 Qxd5 11.Bb3 Qf5 is more advisable for Black.