how can white gain an advantage
If black is copying your moves as white, play the mainline Petroff! 1. e4 e5 2. Nf3 Nf6 3. Nxe5, and if black plays 3. ... Nxe4, then 4. Qe2!
--Fromper
If black is copying your moves as white, play the mainline Petroff! 1. e4 e5 2. Nf3 Nf6 3. Nxe5, and if black plays 3. ... Nxe4, then 4. Qe2!
--Fromper