Ruy Lopez: Morphy Defense, Modern Steinitz Defense

The Modern Steinitz Defense is 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 d6, the most common fourth-move sideline of the Morphy Defense in the Ruy Lopez. It is also called the Deferred Steinitz or Neo-Steinitz Defense, and Alexander Alekhine, José Raúl Capablanca and Paul Keres played it often.

The idea

Black defends e5 with the d-pawn, as in the ordinary Steinitz Defense, 3...d6. The difference is the inserted ...a6 and Ba4: Black can break the pin on the c6-knight with a timely ...b5, which gives more flexibility. In the ordinary Steinitz White can almost always force Black to give up the strong point on e5; in the Modern Steinitz Black keeps it.

Main lines

Most natural moves are playable for White, including 5.c3, 5.c4, 5.Bxc6+, 5.d4 and 5.O-O.

• After 5.c3, 5...f5 is the sharp Siesta Variation, while 5...Bd7 6.d4 leads to a manoeuvring game.
• 5.Bxc6+ bxc6 6.d4 and 5.O-O Bg4 6.h3 h5 both give sharp play.
• 5.c4 and 5.d4 are older lines that are not considered testing for Black.

Noah's Ark Trap

After 5.d4 Black can break the pin at once with 5...b5 6.Bb3 Nxd4 7.Nxd4 exd4. Now the natural 8.Qxd4? is a mistake because of 8...c5 9.Qd5 Be6 10.Qc6+ Bd7 11.Qd5 c4, and White's bishop is trapped, as in Steiner–Capablanca, Budapest 1929.

The numbers

On Lichess White wins 49.3% of the 1.1 million games and Black 45.3%. The balance changes with rating: White leads 53.0% to 43.2% under 1400, while from 2200 up Black is ahead, 47.3% against 45.1%. In 6,364 master games over the board White won 36.3%, Black 24.7%, and 39.0% were drawn.