Source: https://www.andrewrobson.co.uk
Sometimes – often – you can gain more by penalising the opponents than by making your own contract. This is particularly true when an opponent has opened 1 NT. Any hand, balanced or otherwise, with sixteen or more points should double 1 NT. This is a “Penalty” double and unless partner is particularly weak with a long suit (in which case he will remove the double) he is expected to Pass.
The carnage can be horrific, especially when the doubler has a long suit to lead…
Dealer South Both Vul
 9 7 5 4 K J 4 9 7 6 Q 10 8 |
||
| A Q6 2A K Q J 4 27 5 4 |
8 6 3 2A Q 10 8 386 3 2 |
|
| K J 109 7 510 5 3A K J 9 |
| West | North | East | South |
| 1NT | |||
| Dbl | Pass | Pass | Pass |
There are those who would claim that South should not open 1 NT (12-14), as he holds two suits unstopped. I am not one of them – a 1 NT opener is by far the most descriptive opening bid and only occasionally results in trouble.
West led ♦ A and played out all his five remaining s, East discarding 2, 3, 6 and 2, ♣. By throwing low cards in the suits he didn’t want, East signalled for ♥s whilst retaining all five of them. West switched to 6 to J and Q, and East accurately returned 8. West beat declarer’s 10 with Q. He cashed A and led 2. East beat dummy’s 4 with 10, cashed A felling dummy’s K, and took the last two tricks with 8 3.
Declarer had not made a single trick, losing 2000 points. Rather better for East-West than bidding and making their own contract!
THE RULE OF SIXTEEN: If an opponent opens 1 NT and you have sixteen + points, you must double – a penalty double.
