I probably have to explain the auction:
1C = 3+, could be 4-4 in the minors.
1H = 4+ spades
1NT = natural but denies 4 spades. We frequently rebid 1NT with a singleton spade.
2D = artificial GF.
3C = natural.
3H = natural, but with 5-5 I would have bid 3H last round.
After 1NT I had several options.
I could have bid 3S forcing, showing a slam try with a strong 6+ spade suit. I decided against this because (a) my partner would likely bid 4C, after which I couldn't find out whether he had wasted diamond values, and (b) if my partner had a small singleton spade we could easily belong in clubs.
I could also bid 4D, splinter. Although a splinter with an ace is sometimes not a good idea, here it does convey the most important message. But again, we would have a hard time getting to 6C.
In the end I chose to bid 2D to see if I could learn more about my partner's hand.
Over 2D, partner's first priority if to bid 2H with 4. For the rest our style is to bid naturally with a strong preference for the cheapest calls. So 3C showed a good club suit, I could expect AKxxx. This was good news. On the other hand, he would open 1NT with many balanced 14-counts holding AKxxx, and would open many 11's. The hand also became difficult in terms of strain: if partner had a small singleton spade then 6C seemed likely better than 6S.
My 3H call was natural, and so was his 3NT. I figured that by bidding 4S now, I was showing a slam try with 6-4 in the majors. If partner had a bad hand for me then he would pass and we would likely be in the safest game. I thought that I had to have a slam try, I can't be looking for the best game by first introducing a 4-card heart suit (while I know that partner doesn't have hearts) and then pulling 3NT to 4S. Which other games could I be interested in?
Still, I feel like I didn't bid enough on this hand, and I also didn't tell partner that I had a good hand for clubs.
On the other hand, I blame partner for first bidding 3NT (inconceivable to me with no diamond card plus such great fitting honors) and then passing 4S with such prime cards. However, I could have known that it was not clear to partner that I was making a slam try, and our auction would likely have been better had I started with a clearer bid such as 3S or 4D.
Your thoughts?