Hand Balance
The balance, or suit distribution, in your hand is critical in making good bidding decisions. Balanced hands are generally one of the following hand shape: 4-3-3-3, 4-3-3-2, or 5-3-3-2. Balanced hands are apt to produce less distribution points, but can be beneficial if you and your partner decide to settle on a contract in notrump. Balanced distribution generally allows a hand to promote itself during game play.
Semi-balanced hands are hands which don't fall into one of the shapes listed above, but can be considered balanced after some early bidding between you and your partner. Semi-balanced hands are most often found in the following shapes: 5-4-2-2, or 6-3-2-2. With stoppers in the short suits, it is sometimes better to open with a notrump bid with these suit shapes than bid the long suit. This is especially true if you and your partner are using the 5-card Major system, with better minors. If your hand has a long minor suit, and is short in the major suits, an early 1-level bid in the minor might not convey the strength of your hand.
An unbalanced hand is one in which you have a number of cards in one or two suits, and very few in the others. Unbalanced hands can be very advantagous when you and your partner are attempting to establish a contract in a suit. The long suited nature of your hand will possibly bring more trump to the table. The real benefit of an unbalanced hand, however, is that with less cards in the non-trump suits your are able to trump your opponent's possible winning cards.