Opening Bid:   Three Notrump - 10+ HCP

5-5 in the Minors
How often do you hold a hand with 5-5 in the minors?  Often enough that we call it an Unusual Notrump hand.  If your opponent opens a major, you can describe this hand with a jump to 2NT.  But what do you do with that same hand if you are in first seat?  All of the strong club systems use an opening bid of 2NT to show it, but the KD system uses 3NT to show 5-5 in the minors.

How many points?  At least 10, and if you only have 10, they should all be in the two minor suits.  This hand, for example:
Three notrump is not only descriptive for your partner, but it is also preemptive for the opponents.  They have to start at the 4-level to find their major suit fit.  If you open 1, hoping to rebid some number of clubs later in the auction, you will give your enemy plenty of room to explore.  By the time the bidding returns to you, you might be reluctant to show that other minor.

Finally, If you find a misfit and your partner holds the majors, and she passes, at least you will get to play the hand.

Little Known Agreement
The above is commmon to all forcing club systems, whether they use 2NT or 3NT to descibe a 5-5 hand with minors, but here is a little known agreement that you should consider with either treatment:
    Responder Jumps to Four Notrump
    Nope, it's not Blackwood.  Responder is asking this question:
      "Partner, are you interested in slam if you know that I have a good hand?
      If you are, please bid 6, but I may correct to either six or seven of either minor."
You may be asking, "What's the upper point-count range to open 3NT?"
Although generally the minimum point-count to open this bid is 10 points, there is no upper limit.  As a guide, though, use this rule to help you with big hands...
  • Bid game if your partner simply responds with either 4 or 4
  • Bid a slam if your partner responds with either 5 or 5