Opening Bid: Three No Trump
When an opponent opens either 3 or 3 as a preemptive minor we do find it often presents a problem for us because of the level of the bidding, but we still have the rest of the 3-level to find our major. But suppose your RHO opens 3NT, which is alerted by his partner as a preemptive minor? Life just got a little harder, because now we have to start looking for our major suit fit at the 4-level.
3NT - A Preemptive Minor Suit
The system agreement is that this opening bid promises at least a 7-card minor headed by either the ace or king, or sometimes a long suit headed by the queen-jack-ten. Partner may pass or decide the hand would be better played in the minor. If he bids 4 the opener will either pass or correct to diamonds.
A popular agreement is to open 3NT with a solid minor, but invariably the hand is played from the wrong side of the table. Open 3 or 3 with a solid suit and let your partner bid 3NT if that's a contract that can make from his side.