This convention ‘inverts’ the normal meanings of the single and double raises of a minor suit. Thus 1♣-Pass- 2♣ is stronger than 1♣-Pass-3♣. The single raise is forcing for one round, enabling responder to make the bid on both invitational and game-going hands.
Playing inverted raises, you would raise 1♣ to 3♣ or 1♦ to 3♦ with Hand 1. Even if this contract does not make, it is very likely that the opponents could have made 2♥ or 2♠. The benefit of playing inverted raises is even clearer if you hold the second hand and partner opens 1♦.
You can bid 2♦, forcing. In standard methods, you would have no satisfactory response.
