Source: http://www.nzbridge.co.nz/ By Richard Solomon
No matter what form of the game you are playing, you want to be on the right end of the part-score battles, both in the bidding but also in the play and defence. Many examples deals are about the action in playing or defeating a slam. Here, let’s look at a part-score deal where it looks like North-South won the bidding but the victory will not be that great if the play lets South down:
Looking at the North-South hands, there appear to be five losers, three diamonds, a club and the trump ace. None of those losers are going to disappear especially after the three top diamonds are played. South has to do the best they can to avoid any more losers, or in particular, a second trump. If West has 
A10 and two or three others, then there is no hope in avoiding the second trump loser. If the suit breaks 3-2, then unless West has a singleton spade, the contract looks safe.
Yet, there is one more danger lurking, the actual lay-out above, which becomes a definite reality when East has overcalled without any diamond honour.
What, therefore can South do? Winning the 
A and then crossing to the K to lead a heart towards the South hand (East’s ace goes up “on thin air”) does not work. East plays a third round of spades (10) with South throwing the losing club but when the 9 comes next, one trump loser becomes two, no matter with which card South ruffs. Down one, again.
The winning line is quite simple. When West switches to the spade at trick 4, play dummy’s king. Capturing East’s queen is an absolute irrelevancy as there is no entry to dummy to play a third spade to discard the club. South knows that. Thus, win K and play a low heart. East wins and plays a second spade won by South’s ace. Now, draw trumps and claim conceding a club trick…making 2.
A little care and forethought was all that was needed. The opposition bidding had helped too. “Only a part-score” you may say. 2 or 3% chucked away playing Pairs, 5 imps playing Teams. Can you afford to do that? I can’t and I doubt that you can.