What to Rebid?

Playing matchpoints. Both you and the Opponents are vulnerable.

Here is your hand:
♠AKJ32
♥J96
♦AT54
♣9

You are Dealer and open the bidding 1♠. The Opponents are silent during the bidding. Partner respond 1NT. What does Partner's 1NT mean and What is your call?

Show Answer

2♦.

Partner should have about 6 to 10 HCP (High Card Points) and fewer than three ♠. Partner is NOT promising a balanced hand. They did not OPEN 1NT they RESPONDED 1NT just because they did not have enough points to bid a new suit at the 2 level.
With a lower ranking suit than the one you originally bid you are supposed to take Partner out of their 1NT bid since weaker hands tend to play better in a suit contract.