Morphy Defense, Fianchetto Defense Deferred

The Fianchetto Defense Deferred, 4...g6, adds the kingside fianchetto of the Fianchetto Defense (3...g6, also called the Smyslov Defense) to the Morphy Defense. Because ...a6 and Ba4 are already included, Black has ...b5 available to break the pin on c6. The position is often reached by transposition from 3...g6. White usually castles with 5. O-O, and 5. c3 and 5. d4 are the main alternatives. The line is uncommon, and engines give White a slight edge.