FrancesHinden, on Sep 20 2005, 03:13 PM, said:
Given that the auction is contested, I would rather have opened my longest suit on an unbalanced hand.
Comparing any two hands of differing distribution, it might be said that one is more balanced than the other. But in absolute terms, whether a hand is described as "balanced" is down to an arbitrary cut-off definition.
The (perhaps temporary) loss of the 5 card suit by opening 1NT is to some extent compensated for by partner's confidence in your narrower range of high card strength, his confidence of finding at least 2 card support for any suit that he intends to introduce (or in defence of opponent's suit) and his (perhaps limited) confidence that you do not have a 6 card suit, all of which confidence is lacking following a 1-suit opener.
No-one bats an eye at opening 1NT with 5332 shape and yet in the face of competition the 5 card suit remains potentially concealed and you still may have only doubleton in any suit of interest to partner. Perhaps if responder has 5-5 shape he can be confident of at least a 5-3 fit in one of his suits if you are proscribed from opening 1NT with two doubletons.