Playing a 25c IMPS robot tourney on BBO, I picked up:
The bidding went:
Partner opened it 1C, RHO overcalled 1D and I bid 1H (forcing). Partner now bid 1S and I bid 2D (fourth suit forcing).
At this point, North bid 2H showing 3 hearts. What is your bid? Essentially, I have diamonds well stopped and the danger is that if North has several diamonds, West will get a few ruffs.
At the table, I could not think of a way to get North to tell me how many diamonds he had, so I shrugged and bid 4H. It went down because this was the full deal:
As anticipated, West got two ruffs to scupper 4H. 3NT was the right spot to be in. How could I could have gotten there? By bidding 3D over the 2H. Now, North with 3 diamonds and the queen would have bid 3NT.