233

This brings opener back to life. When responder shows a control in hearts, opener has enough to take the partnership to 6 Spade

Here opener has enough to go for slam once spades are agreed, but doesn't want to immediately jump to Blackwood without a control in the club suit. Instead, opener starts a control-showing sequence with 44, and responder cooperates by bidding 4 . Opener is still worried about clubs, but has too much to give up on slam. Blackwood still won't resolve the problem in clubs, so opener can try another control-showing bid, even though it takes the partnership beyond game.