Discipline in the bidding means never having to say you’re sorry!
South’s sparse collection certainly fits the mold of a weak jump shift response for most advocates of that treatment: six or more cards in the bid-suit with overcall values that wouldn’t exceed what you’d have for a (very) weak two-bid as opener. Not for the faint of heart!
And faint South’s heart must have been when he converted his partner’s choice of three notrump to four spades to violate a fundamental bidding principle: A preemptor doesn’t make a voluntary second bid.
Partly from eliminating any other choice as less attractive, West picked a fourth-best club for his opening lead to immediately confront declarer with at least four losers.
South might have tried a second-round diamond finesse to get rid of his club loser, but he played with less imagination to end down only one for the loss of two spades, one heart and the club established by the opening lead.
But how about North’s choice for the final contract?
Thanks to South’s ten of heart being a great combining value and East’s almostcertain opening lead of a low diamond against the ninetrick game, North would have skated for home with one spade trick, four hearts, three diamonds and the ace of clubs.
Of course, South couldn’t know all of those good things were going to happen in three notrump, but he should have known that his partner had made the final choice for the partnership.
Much better for South to have said “pass” at the critical juncture of the auction than “sorry, partner” after the completion of the play in four spades!