Opener bids one club, responder bids one heart. Opener rebids 2NT (18-19 high card points, balanced). Responder raises to 4NT. I take that to be a "quantitative" bid, aiming for 6NT. The reason is that no suit has yet been agreed upon and 4Nt is actually a raise of 2NT. Am I right?
Opener bids one heart, responder bids 2NT (Jacoby, 13-15, four hearts). A opener's "raise" to 4NT IS Blackwood, because "2NT" was really a "raise" of hearts, not a true no trump bid. Is this correct?
Opener bids one heart, responder answers 4 diamonds (splinter), and opener bids 4NT. This is Blackwood because the splinter bid is (de facto) a raise of the heart suit, right?