North naturally thought that South held a stronger hand with a heart stopper, and raised.

South, not having a heart stopper, might have jumped to five clubs, but she advanced with three spades.

This cue-bid suggested game and asked for a heart stopper.

East would have won and led a heart, causing the declarer to discover that his three heart stoppers were not enough.

She could even be a heart stopper if she wanted to be.

Some would think this a cue-bid, asking for South to bid three no-trump with a heart stopper.

South's raise to three diamonds, rather than bidding two no-trump, strongly suggested a lack of a full heart stopper.

And the actual two no-trump bid, in the sequence shown, suffered from the lack of a heart stopper.

He hoped his partner held a heart stopper, and South took the same position.

For most, the raise to three no-trump would deny a heart stopper.