South’s one-club opening was strong, artificial and forcing. North’s pass over West’s two-diamond weak jump overcall was either a bad hand or, as here, a trap pass. North hoped his partner would reopen with a takeout double, which he was planning to pass, converting it into a penalty double.

South, however, understandably rebid in his seven-card club suit. Then North leapt precipitately to six no-trump.

Now East made a bad error in doubling. If he had passed, he would have been able to cash his two top spades, and plus 50 would have given his side 11 match points out of 12. Yes, plus 100 would have been all 12, but South, realizing what was about to happen, ran to seven clubs, putting West on lead.

West led the diamond ten, a strange choice. (North was known to have good diamonds, and South could well have been void. Also, surely East had an ace-king for his double. West should have guessed a major suit to lead.)

Given the reprieve, what did declarer do?

We can see that he can take 13 tricks — four hearts, two diamonds and seven clubs — for plus 1,630 and all 12 match points. But South felt strongly that East had four clubs. And if so, he was four times more likely to have jack-fourth than four low.

So declarer won the first trick with dummy’s diamond jack and immediately played a club to his ten.

Disaster! West took his jack and shifted to a spade for down three, plus 500 and 12 match points.