Strong opening bids 2♦ - game force:

• 24+ HCP, balanced distribution;

• 23+ HCP, unbalanced distribution.

Responses:

• 2♥ - 5+♥

• 2♠ - 5+♠;

• 2NT - negative, no 5M and no 5m and less than 7/8 HCP;

• 3♣ - 6+♣;

• 3♦ - 6+♦.

If you use 2♦ opening 2♣ does not force a game.