When the trump queen fell, he could just survive against West's length.

Five diamonds was a further inquiry, asking for the trump queen.

In either black suit, the guess for the trump queen would be crucial.

The final bid was a reasonable shot, and the contract turned out to hinge on the trump queen.

First he had to guess who held the trump queen.

He would have played South for the trump queen and made the doubled game.

The trump queen fell eventually and gave South his contract.

In seven hearts, the trump queen represented an obvious problem.

And if West leads a side suit, declarer plays him for the trump queen.

West led the trump queen, and South played normally.