Penalty double - the other kind

In the hand from the Dutch training weekend, the double was based on an a bad trump split. This can occur with a stack, of course, or on a void, hoping for a useful holding from partner. This time it was a tip-off and the contract was made, and would have gone down with a normal line of play without any clues.

A more rewarding type of double is when you can tell that the sidesuits aren't breaking well for declarer. Declarer will likely suffer from a shortage of tricks and may loose more than expected because s/he expects trumps to misbehave (when they actually split very well).

Here is an example of that kind from the Swedish first division weekend last December (imps).
I had A76/KT3/QJ8432/9 (nonv/vul) and listened to the following auction:

pass - (1D) - pass - (1S);
pass - (2D) - pass - (3C);
pass - (3S) - pass - (4S);
pass - (pass) - ?

With both minors splitting badly and no slam interest this seemed like a good opportunity and I doubled. The complete deal:

---------------T8
---------------A86
---------------AKT765
---------------T5
J94------------------------A76
J642-----------------------KT3
9---------------------------QJ8432
KJ872---------------------9
---------------KQ532
---------------Q95
-------------------
---------------AQ643

Jackpot! Declarer won the diamond lead in dummy, finessed in clubs and partner shifted to the J of spades to declarer's Q. Ace of clubs ruffed by me, ace of spades and a diamond. This was ruffed by declarer, overruffed by partner who then proceeded to cash three good clubs for +1100.