JoostJa online bridge

♠ A 6 5 3 2
♥ 5
♦ A 9 2
♣ A 8 7 5


South is the dealer and both sides are vulnerable
WESTNORTHEASTSOUTH

Pass
1 ♦ Pass 1 ♠ Pass
2 ♦ Pass 3 ♣ Pass
3 ♠ Pass ???

My bid was 4 ♠ and that ended the bidding.  

It is much better to bid 4 ♣ to tell West that you have ♣A.   You only have 12 HCP but you have a double fit with your ♦A92.   If West has ♥A you can count a possible 5 spades, one heart, a possible 5 or 6 diamonds and a club, totalling enough possible tricks to at least try for slam.  

West had ♠KQ4 ♥A97 ♦KQ10765 ♣6 so even 7 ♦ is the optimal contract for your side.   Diamonds play better than spades since the trumps can not break 4-1.  

The improved bidding sequence will now start with:


South is the dealer and both sides are vulnerable
WESTNORTHEASTSOUTH

Pass
1 ♦ Pass 1 ♠ Pass
2 ♦ Pass 3 ♣ Pass
3 ♠ Pass 4 ♣ Pass
4 ♥ Pass ???


Now what?  

4NT Blackwood makes no sense, we have all the aces, and we don't ask for kings with 5NT after 4NT or something like that.  

A 5 ♣ bid would be our convention "top honnors asking".   West would answer 5 ♠, meaning 2 of them.   East now knows that West has ♠KQ and ♥A and 5 or more diamonds, so the West hand looks something like ♠KQx ♥A(x+) ♦xxxxx(x+) ♣(x+), and West will have some points in diamonds for his opening bid.   Slam looks reasonable, East could bid 6 ♠ now.   Can East revert to diamonds as trumps?   It's all about ♦KQ with West.   What if East bids 6 ♦ after 5 ♠ from West?   After our 5 ♣ convention East would normally bid 6 or 7 ♠, so something else is vague.   Too vague, and there is a better solution: let West decide.  

The winner is 5NT.   5NT confirms all 1st round controls and asks West to bid 7 with extras.   After 5NT West knows East has something like ♠Axxxx(x+) ♥(x+) ♦A(x+) ♣A(x+).   West can now make the big bid of 7 ♦!   A 7 ♠ bid would also lead to good results on average.   6 ♦ by West is another possibility.   If West bids 6 ♦, East can bid 7 with his diamond fit and ruffing tricks in hearts.   But I guess 6 ♦ would suggest better trumps than West has.  

EAST: ♠ A 6 5 3 2
♥ 5
♦ A 9 2
♣ A 8 7 5

WEST: ♠ K Q 4
♥ A 9 7
♦ K Q 10 7 6 5
♣ 6



South is the dealer and both sides are vulnerable
WESTNORTHEASTSOUTH

Pass
1 ♦ Pass 1 ♠ Pass
2 ♦ Pass 3 ♣ Pass
3 ♠ Pass 4 ♣ Pass
4 ♥ Pass 5NT Pass
7 ♦ Pass Pass Pass

A grand slam with only 26 HCP in the combined hands. Will we ever be able to bid like that?