South, with 13 high card points, opens one club, his better minor. North, without a four or five-card major, chooses to raise his partner with five-card support. He has the required ten or more points for an inverted minor raise. He bids two clubs.
South bids two hearts because he has hearts stopped but not spades. North has spades well-stopped and does not need the lead coming up to his hand in either major. He bids three spades (two spades would have also been fine) compelling South to bid 3NT.
The contract: Three no trump by South
The opening lead: The six of spades
If declarer ducks the opening lead, defense will win the queen of spades and four heart tricks. Declarer goes up and wins with the ace of spades. East cannot be let in. Declarer takes the diamond finesse because a heart lead from West cannot hurt the contract. It loses and West continues with a spade.
Declarer wins the king. Declarer takes five clubs, three spades and two diamonds for ten tricks.
There are eleven tricks on a heart lead. The contract is well-positioned with South as the declarer.
The result: Three no trump plus one for +630
-Holdings like AQ, KJx and Kx need the lead coming up to them. Inverted minor bidding gives the declaring side a chance to protect them.
-If North plays 3NT, he loses four hearts and can only make +600.