If South had bid three spades, he would probably have been doubled.

She bid two spades, which East was delighted to hear.

North should have bid five spades, but he held his peace.

But South was not willing to settle for that and bid six spades.

Curiously, South has less chance of success if he bids four spades, as many would.

He bid two spades after a pass on his right.

But in a sense he was right to bid six spades.

This gave East a second chance to bid four spades.

Warned by the opening, South would probably have bid four spades.

That was not a very sensible action; he could simply have bid seven spades.