The bidding: West, with 18 points, opens one club intending to jump to two notrump if partner replies. Of course, if partner passes, a simple rebid of one notrump would show this strength of hand.
North, with twelve points and four-four in the majors, makes a takeout double. East is too weak to make a bid and South has a decision to make. He knows his side needs more than half the 40 points available in addition to several trump tricks to set the one-level contract.
It also is apparent that either his partner or the one-club opener has 18 or more points. South is not a gambler and does what he should.
South cannot leave it in and picks diamonds because of the king and the fact that partner will not have a five card major but could have five diamonds. There is also hope that someone may bid over diamonds and diamonds gives everybody room to do that.
The contract: One diamond by South
The opening lead: The ace of clubs
The play: In one diamond, declarer ruffs the opening club lead and draws trump in three rounds. There are no ruffs in the short trump hand so declarer need not wait drawing trump. Declarer plays a heart. Defense wins the trick and plays back a club. Declarer uses his last trump and plays another heart. Defense win their last club and two spades in addition to two hearts.
Result: 1”S+1 +90
The contract: One club doubled by West
The opening lead: The queen of hearts
The play: Against 1 x, North will lead the queen of hearts. West wins the King and plays a heart towards his ace. South follows suit and declarer wins the ace.
Declarer then cashes a top spade and crosses to the queen of trump to play a small spade to the king. South follows and West gets seven tricks.
Result: 1 xW= -140
Note: One needs at least a combined 22 points, mostly favourably placed and a handful of trump tricks to set a one-level contract.