West is dealer, vul none
My partner and I clearly misbid this hand as we played in 3NT by S and made 6. (We should have made 7, as the diamond finess is working. Partner got confused on how to handle diamonds after they split 4-0. We even got a gift at trick 1 when the 4♣ was led and East follows with the 3.) I won't bother to discuss the misbidding, except that I may have started it by opening the North hand. BTW 2/1 GF.
How would you suggest bidding this - opponents are silent. I think the best contract is 6D. NT is vulnerable after a heart lead if the K♦ is wrong.

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