The Gates double is an extension of any conventional no-trump defense like Astro or Cappelletti that uses a penalty double. The Gates double is used by a passed hand that cannot possibly have the strength to make a natural penalty double.
| Pass||Pass || 1NT|
- A single-suited club hand, since a 2 overcall is artificial showing any one-suited hand. A Gates double allows the overcaller to show clubs without getting the bidding up to the 3-level.
- Both minors, since a 2NT overcall promises at least 5-5 in the minors and forces the bidding up to the 3-level. A Gates double could be made with lesser distribution or strength at the 2-level.
- Both majors, with longer spades than hearts. Playing regular old Cappelletti, a hand with both majors is shown via a
2overcall. If partner then corrects to 2with equal length in both majors (e.g. 3-3), then the better spade fit is missed whenever overcaller is 5-4.