Alburt Variation
Alekhine's Defense
1.e4 Nf6 2.e5 Nd5 3.d4 d6 4.Nf3 g6 5.Bc4 Nb6 6.Bb3 Bg7
Black fianchettoes with ...g6, and White's bishop goes to c4 and b3.
Practice this lineThe idea
After 4...g6 5.Bc4 Nb6 6.Bb3 Bg7, Black's bishop aims at the e5 pawn and the long diagonal. Fischer played 4...g6 in game 13 of his 1972 match against Spassky, and Lev Alburt has played it often. Wikipedia names 5.Bc4 the Keres Variation.
Plans for White
Keep the bishop on b3 aiming at f7, and gain space with a4 (the Keres line goes 7.a4) to harass the knight on b6. Castle and support e5 with Qe2 and Re1.
Plans for Black
Castle, then hit e5 with ...dxe5 and ...Nc6, or play ...a5 to stop a4-a5. Black's bishop on g7 becomes strong once White's center is broken, so the plan is to open the long diagonal.
Watch out for
For Black, the a-pawn push. a4 and a5 can drive the knight on b6 away, so be ready with ...a5 or a new square.
For White, the long diagonal. Once e5 is exchanged, the bishop on g7 hits d4 and b2, so keep d4 protected and don't let the queenside pawns become loose.