After 2 Way New Minor Forcing

This hand caused me a problem at the regional in Lake Geneva. Playing IMPs I held
Tx
KJx
AQJxx
Qxx
I opened 1 Diamond, my partner responded 1 Spade and I rebid 1 Notrump. Now my partner bid 2 Diamonds showing some game-forcing hand. This is a nice convention because it allows you to pass information back and forth at a conveniently low level to decide on a strain for your game, or perhaps to investigate slam. Still, you can't be lazy with your bids here. This is apparently a very simple situation, but what do you bid at your 3rd turn?


I didn't think much about this one beyond the fact that I held 5 diamonds to the ace-queen-jack and hadn't shown them yet. So 3 Diamonds it was. I failed to imagine my partner's possible problem on this auction...over 3 Diamonds, his 3 Heart bid looks natural here and 3 Spades is definitely natural, so space is suddenly at a premium. Forced into a guess, my partner reasonably went with 5 Diamonds holding Qxxx x Kxxx AKJx. This was a silly contract, down off the top with 3 Notrump cold on most layouts and difficult to defend on the layouts where it is beatable. What was the problem?

On the theory of game before slam, my hand looks very well-suited to notrump play. I have slow honors in both of the unbid suits and really don't want to play diamonds unless my partner suggests it (and insists on it over my 3 Heart continuation). I now believe that I should have continued with 2 Notrump over 2 Diamonds--the auction is still low enough that we can reach diamonds if that is where the hand belongs. I thought this was an interesting problem because it is so easy to get lazy during these auctions--even when it looks like you have plenty of space, you have to imagine partner's problems and make sure you are making the most descriptive, economical bid.