3.Nc3
Owen's Defense
1.e4 b6 2.d4 Bb7 3.Nc3 e6 4.Nf3 Bb4 5.Bd3 Nf6 6.Bg5 h6 7.Bxf6 Bxc3+ 8.bxc3 Qxf6
White defends e4 with the knight, and Black pins it with ...Bb4.
Practice this lineThe idea
After 3.Nc3 e6 4.Nf3 Bb4 5.Bd3 Nf6 6.Bg5 h6 7.Bxf6 Bxc3+ 8.bxc3 Qxf6, both sides have traded a bishop for a knight. Black keeps the light-squared bishop and has an active queen; White has the center and a lead in development. MCO-15 favors White.
Plans for White
Castle and use the center. The c3 pawn supports d4, and with e5 White can hit the queen on f6 and gain space. White's knight and bishop work well in the closed center.
Plans for Black
Castle, develop with ...d6 and ...Nd7 or ...Nc6, and hit e4 with ...e5 or ...d5. Black's bishop on b7 and queen on f6 both pressure the long diagonal, and White's doubled c-pawns can become targets.
Watch out for
For Black, e5 with tempo. Once White plays e5, the queen on f6 must move and Black's pieces can get pushed back.
For White, the doubled c-pawns. After Bxc3+ bxc3, they're a long-term weakness, so White should play for activity in the center before Black can attack them.