A direct cue bid in a suit the opponents have opened is known as a Michaels cue bid. If the opponents open one of minor, a cue bid of 2 of that minor shows the majors; if they open one of a major, it shows the other major and one of the minors. A jump cue bid, conversely, asks partner to bid 3NT with a stopper in the opener's suit.
When they open with a weak 2 bid, it gets more complicated. Jenn and I, along with many pairs, use a convention sometimes called Leaping Michaels. With a 2-suiter including the other major and a minor, we jump to 4 of the minor. For example, if RHO opens 2H and I have 5 clubs and 5 spades I can jump to 4 clubs to show the 2-suiter.
So, having this agreement, what does a direct cue bid of 3 of their suit mean? I confess that I had not discussed this with Jenn or any of my other partners. Does it still show a 2-suiter, but perhaps weaker than a jump to 4 of a minor, or does it ask partner to bid 3NT with a stopper, just as if the opponents opened 1 of the major?
I was playing on-line the other night. RHO, non-vul vs vul, opened 2 Spades. I held:
It looks like 3NT would have a good chance if partner had, say, Qxx of spades, as diamonds are likely to run. If not, 5 Diamonds may be right if partner has something useful in hearts or clubs. Since I was playing with a pick-up expert partner, I probably shouldn't have risked a 3 Spade cue bid, but I did, hoping partner would be familiar with Leaping Michaels and interpret this as asking for a spade stopper. A more practical solution would be to just bid 5 Diamonds or 3NT and hope for the best.
Unfortunately, LHO raised to 4 Spades and partner, holding
bid 5 Hearts, which went down. 5 Diamonds or 5 NT would have made, and we'd even have done well doubling 4 Spades, which would have gone for -500. He expected me to have hearts. I asked him if he played Leaping Michaels and he did, but he said, correctly, that to expect him to work out that this wasn't showing hearts put too great a strain on a casual partnersship. If you were playing with your regular partner, would you have gotten this right?