The Bidding: North opened two diamonds in second seat. The probability that he is preempting a partner with points is highest in second seat. The bid describes his hand quite nicely so he opens a weak two.
With 15 points and a five-card suit, South is interested in game. He bids 2NT which is forcing and asks partner to bid a feature. Asking for a feature is quite useful over diamonds because South wants to play 3NT, not five diamonds. A feature is an ace or a king in a side suit. QJ10 will do in a pinch.
North having a spade feature goes well with South’s doubleton queen. He also has three diamonds to an honour. 3NT should be a solid contract.
The contract: Three notrump by South
The opening lead: The jack of hearts
The play: West ducks the opening lead and wins the continuation. To set up clubs, declarer needs three heart stoppers or two stoppers and a holdup because declarer does not have the ace or king. A hold up is unlikely to work because East has three hearts, and when he wins the king of clubs, he has a heart to return knocking out declarer’s queen. Now West has both a club entry and a spade entry to run his hearts.
Declarer cannot set up his clubs. Instead he knocks out the spade ace for two spade tricks, six diamonds and two hearts for 10 tricks.
The result: 3NT making plus one for +430.
Without the weak two diamond bid:
If North does the unlikely and passes instead of pre-empting in second seat, East will also pass.
His spade suit is too weak and disaster could strike because he has no control of the trump suit.
South will open 1NT in fourth seat and North will just bid 3NT. North is too strong to invite. He can count points for his fifth and sixth diamonds because it is very likely declarer will be able to get to them. It is a strong diamond suit and the hand has good possibilities of a spade entry or two.