After a weak jump, bid one higher

Yesterday, we saw what would have been an effective atypical pre-emptive opening bid. If the opponents are going to produce wild leaps into the stratosphere, you need to know how to defend yourself. Look at the North hand in the diagram. South opens one spade, and West intervenes with three diamonds, a weak jump overcall. What should North do?

Yes, West’s bid would normally feature only a six-card suit, but he was swayed by the unfavorable vulnerability and also wondered if his side might make three no-trump.

After a weak jump overcall, responder, with support for partner’s major, should bid one level higher than originally intended.

Here, a three-spade response would promise a normal single raise. With his actual game-invitational limit raise, North correctly jumped to four spades. And if his hand had been even stronger, he would have cue-bid four diamonds, which would have said nothing about his holding in diamonds.

Against four spades, West led the heart five. East won with his king and cashed the ace, West dropping a sneaky two. When East led another heart, South was not sure what to do. Discarding risked West’s ruffing with a low trump. Then the spade ace would have been the setting trick. Eventually, South ruffed with his spade king, and West inwardly smiled when he followed suit. However, when West took the next trick with his spade ace, he was endplayed.

He tried the club eight, but dummy’s nine forced out East’s queen. South won with his king, drew trumps, and claimed four spades, one heart (dummy’s queen), one diamond, three clubs and a diamond ruff in the dummy.