Normally, the following doubles are for penalty:
- after making any penalty double (or a penalty pass), all later doubles are for penalty;
- on a natural notrump bid;
- after we have found our fit;
- after any natural notrump bid by our side;
- after we preempted;
- after making a lead-directing double;
- when the partner has accurately limited his hand (such as 1♥-(/)-1♠-(/)-2♥-(3♣)).
- when it is made late in the auction;
- when all suits have been shown, or when there is only one suit not shown.