Key ideas
- The main line is 5...O-O 6.O-O Nbd7 7.Qc2 c6, when Black's last problem is the c8 bishop. The standard solutions are ...b6 with ...Bb7 or ...Ba6, and the freeing ...dxc4 followed by ...e5 or ...c5.
- White's typical set-ups put the queen on c2, a knight on d2 or c3 and the bishop on f4 or b2, all preparing e4. 8.Nbd2, 8.b3 and 8.Bf4 are the main tries at move 8.
- A typical sequence is 8.Bf4 b6 9.Nbd2 Bb7 10.e4 dxe4 11.Nxe4 Nxe4 12.Qxe4. The centre has opened and the g2 bishop comes to life, but Black has traded pieces and is ready for ...c5 or ...Nf6.
- If Black allows e4 without being ready to meet it with ...dxe4 and a break, White gains space and the e5 push can cramp Black's pieces.
Plans for White
Complete development with Qc2, Rd1 and Nbd2 or Nc3, and push e4 at a moment when Black cannot reply with ...dxe4 and an easy ...c5 or ...e5. If Black's queenside stays passive, pressure on the c-file and against c6 is the long-term plan.
Plans for Black
Keep d5 firm with ...c6, develop the bishop with ...b6 and ...Bb7 (or ...Ba6 against c4), and prepare ...c5 or ...e5. Taking on c4 is often useful once White's pieces are committed, since it opens the long diagonal for a bishop on b7.
For the wider picture, see the Catalan Opening guide.