NO TRUMP HANDS

Hands that have no singletons, no voids, and no more than one doubleton are said to have no trump distribution (note that the American Contract Bridge League, or ACBL, recognizes 5-4-2-2 hands as valid for this, but this is not a definition you should apply before at least becoming an intermediate player). The most distributional hand possible under these conditions is 5-3-3-2, and the only other possible distributions are 4-3-3-3 and 4-4-3-2. These hands are alternately called no trump hands and balanced hands.

If you have no trump distribution and 15-17 HCP, open 1NT, provided the 5-card suit in a hand with 5-3-3-2 distribution is not a major since showing the 5-card major is more important; you can always show your strength later but want to find the major suit fit quickly if it's there. Not all players will follow this guideline, however, and you certainly may consider 1NT as an alternative with NT distribution and a poor 5-card major that lacks honors.

If you have NT distribution and 20-21 HCP, open 2NT. You won't find many of these hands, for obvious reasons, but when you do, your partner will almost always have enough strength to help you out: if you have a 20-HCP hand, each of the other players, including your partner, will average about 7 HCP, and game contracts are within reach in most of these cases.

So what happened to 18-19 HCP? In that case, start with one of your better minor and jump-bid in NT when your next chance to bid comes around. Some people extend this to a jump bid in NT over any 1-level bid in a suit, and you may agree to do so as well. These little details are what you and your partner must hash out in order to work together as a successful team.

All of this may seem rather limited, but that is just an effect of the distribution. The difficulty inherent in playing NT hands requires that the opening bids have a little more strength since the opening bid can end up being the final contract. Likewise, the distributional requirements are such that they provide a great deal of flexibility in your partner's responses, and that is where NT bidding gets more interesting.