Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. d4/4...exd4/5. O-O/5...Nxe4/6. Re1

= Scotch Gambit Accepted =

6. Re1!
White pins the greedy knight on e4. As f5 would be too slow and Qe7 is still a major piece pin, d5! is the only sensible followup.

d5 is only temporary, however, as Bxd5! followed by Nc3! taking advantage of both pins on the heavy pieces equalizes. An immediate Nc3 is an option as well, though less common.

Theory table

 * 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4.d4 exd4 5. O-O Nxe4 6. Re1