A third seat light opening, especially in a major suit, will act preemptively to make it harder for that player to enter the bidding.
However, it creates two problems:[6] The traditional way to show good support for opener's suit is to jump to the three-level (e.g. 1♥ – 3♥).
Owing to its role in the competitive bidding of part-score contracts, Drury is advantageous primarily in match point scoring events.
[7] Murray's presentation of the original convention included the following features: A rebid of 2♦ shows a full opening.
With a good hand (say 15 or more points) opener may simply jump to game (four of the major suit).