When an opponent opens the bidding with 1 or 1, the immediate overcall of 2NT shows at least 5-5 in the minor suits (that is, at least five clubs and at least five diamonds). If the right hand opponent (RHO) of the partner of the 2NT bid passes, that partner is expected to bid the minor suit that he prefers at the three-level. The unusual notrump applies the principle that when the natural meaning of a bid is not generally very useful, it is profitable to agree that it means something somewhat opposite. That is, while natural notrump bids show a strong hand with balanced distribution, the unusual notrump shows a weak hand with very unbalanced distribution.