Cappelletti convention
Cappelletti (also called Hamilton and Pottage) is a defensive bridge convention used in the card game contract bridge to compete or interfere in the auction when an opponent has opened one notrump (1NT). It is usually attributed to Michael Cappelletti and his longtime partner Edwin Lewis, but the origin of the concept has also been claimed by Fred Hamilton, John Pottage and Gerald Helms. Cappelletti can show a variety of one- and two-suited hands while retaining the penalty double for stronger hands.