I am dealer, West, NS vul.

♠ AKJ107
♥ AJ104
♦ 52
♣ 62
 
The bidding:

We play standard. 3♣=4th suit game forcing.

My partner’s hand was:
♠ 2
♥ K3
♦ AKQ10963
♣ 1093

He said my bid showed 6 spades and I should bid 3♦. 5♦ made at other tables.

What do you think?

Hi Margaret,

I think there is no “right” answer here. Over 3♣ fourth suit GF, normally it sounds like your bids are:
3NT=54 shape with club stopper
3♠=6+♠
3♥=5+♥
3♦=3♦.
However, there are some problematic hands such as a 5=4=2=2 or a 5=4=1=3 shape with no club stopper – in that case, you will have to do ‘something’! With a 5=4=2=2 shape it is usually better to rebid 3♦ so that if you could instead rebid 3♥ or 3♠, they will be “real” bids showing your extra shape (rather than a “I could still be 54”) – but also, if you can bid 3♦ ith a 5=4=2=2 shape (with no club stopper), it allows partner to bid 3♥ or 3♠ over your 3♦ to establish the trump suit at a lower-level so then you and partner can diagnose if there’s a potential slam (i.e. imagine if you had to rebid 3♠ when you have the 5=4=2=2 shape — now partner cannot really set the trump suit to allow cue bidding, and he will have to either bid 4♥ or 4♠, or jump to 5♥ or 5♠. 

Having said that, with a very good five-card spade suit (such as your AKJ107), you can in fact treat that as a six-card suit and rebid 3♠ (which is what I’d definitely do if my shape was 5=4=1=3 with good spades), but with 5=4=2=2 and strong spades, you have a choice between 3♠ or 3♦ (my preference is 3♦). 

However, as to what the actual auction/hands were, I think it’s best for responder to bid 4♦ over 3♠ – there’s no need to commit to spades just yet. Bidding 4♦ just emphasises good diamonds, and if opener has a decent six-card spade suit, opener can still suggest to play in 4♠ by bidding 4♠ over 4♦ (i.e. if opener has a 6=4=2=1 shape, opener would bid 1♠, then 2♥, then 3♠, but then if responder bids 4♦, opener can now raise to 5♦).

Hope that helps,
Andy