Opener is Limited. Opener's 1 NT hand is limited to a narrow range of HCP and distribution -- but responders hand is unlimited. Therefore, responder must find the best contract. (Any time one partner makes a limited bid, the other partner is automatically the captain -- in any bridge bidding system.)

Always Look for a Major Fit. The primary goal is always to find a major suit fit. Experience shows that a hand that can take nine tricks in No Trump can usually take ten tricks in a major suit if an 8 card or better trump fit can be found.

The Winning Margin. In competitive bridge, a 20 point difference (making 4 of a Major rather than 3NT -- 420 vs. 400) is often the difference between winning and losing.  Therefore, Duplicate bidding systems try to find a major fit whenever possible.

First Priorities.

All responses to 1 or 2 No Trump openers or overcalls center around the Stayman and Jacoby Transfer conventions.

These conventions will find 4-4 and 3-5 major suit fits. Responder must use either Stayman or Jacoby with any four or five card major suit if he is to bid at all at the 2 level. Failure to bid either of these is a clear sign to opener (and opponents).

Not Optional. They are not optional bids to use occasionally if you feel the urge -- you must use them when the proper situation arises. Your opponents are entitled to believe your bids are consistent, as is your partner.

We have no non-conventional suit bids at the two level over 1NT - and neither do most other duplicate players. 2ª, 2©, 2¨ and 2§are all conventional bids -- not natural.