Quantitative 4NT - invitational to slam.

• partner last bid was a natural notrump opening or rebid:

  • • 1NT - 4NT;

    • 1♣ - 1♥ - 2NT - 4NT;

    • 1♦ - 3NT - 4NT;

• 4NT is the first rebid by the strong 1♣ or 2♣ opener: 

  • • 1♣ - 1♦ - 2♦ - 2♥/2♠/2NT - 4NT;

    • 2♣ - 2♦ - 4NT = 10-trick notrump hand;

• partner opening was 1NT or strong 2NT:

  • • responder uses Stayman, then jumps to 4NT: 1NT - 2♣ - 2♥ - 4NT = invites 6♠ or 6NT;

    • responder transfers, then jumps to 4NT: 1NT - 2♦ - 2♥ - 4NT = invites 6♥ or 6NT.