Post date: Mar 28, 2013 7:57:18 PM
If you say 1NT and Partner responds 2Club, he is using Stayman Convention.
Stayman is asking for a 4-card major.
If you have 4 Hearts, respond 2Heart.
If you have 4 Spades, respond 2Spade.
If you have 6 or more of each of these, respond 3 of the corresponding suit.
If you have less than 4 of both of these, respond 2Diamond.