Morphy Defense, Møller Variation

The Møller Variation, 5...Bc5, places the dark-squared bishop on its most active diagonal at once, aiming at f2 and supporting e5, while postponing ...b5. That delay gives White extra choices. The usual reply is 6. c3, preparing d4 with tempo against the bishop. After 6...b5, 7. Bb3 transposes to the Neo-Arkhangelsk, while 7. Bc2 keeps the bishop on the b1–h7 diagonal. Black can also castle with 6...O-O, when 7. d4 Ba7 is the normal course. Alternatives include 7. d3, 7. Bxc6, and 7. Nxe5, which relies on the fork 7...Nxe5 8. d4. Without ...b5 played, 6. Bxc6 is also possible, and 6. d3 transposes to the Anderssen Variation. 6. Re1 is the second most common reply.

The line is named after Jørgen Møller, who analyzed it in Tidskrift för Schack. Alekhine used it early in his career but later came to regard it as dubious, and it has never been widely adopted. Engines give White a slight edge, and White scores well in online play.