What is Drury convention?

The Drury convention is a bridge convention, used to show a game-invitational major suit raise by a passed hand while guarding against a light opening by partner in third or fourth seat. It is initiated by an artificial and forcing 2♣ response by the passed hand to a 1♥ or 1♠ opening by partner. The 2♣ bid shows at least 3-card support for opener's suit with 10-12 support points and asks opener to clarify the strength of their opening hand. The convention is also known in Europe as "Toronto".