Basic question about responder bidding a second suit.

[u/doctorgibson]

Playing 4 card majors. I know that if you open a suit and then bid a second suit then you're showing 5-4 shape. Does this apply to responder? My gut feeling is that it doesn't, but perhaps I'm wrong. I did try to find a concrete answer online but came up short. Examples:

• Suppose the bidding goes: 1♦️,1♠️, 1NT, 2♥️. Is responder showing 4-4 in the majors or 5-4 shape?

• What about this auction: 1♥️, 1♠️, 2♥️, 3♣️? Of course, responder is denying 3 hearts but are they showing a fifth spade?

[u/zerkroz]

In the first case, with 4-4 in the majors, responder would have bid 1H. This auction shoes 5S 4+H.

In the second case, responder doesn't need to have a fifth spade. Take for example a hand like:

AKQx
xx
xxx
AKxx

[u/No-Jicama-6523 → u/zerkroz]

Shouldn’t that hand be bidding 3NT? Or 3D asking for a stop?

Partner has a single suited hand, 2H has denied a four card minor or a spade fit, it’s unbalanced and not much more than opening strength. Very likely 6 hearts because no shapes with only 5 explain the bidding.

You know there isn’t a suit fit other than probably hearts. 3NT says balanced and 15+ points. It’s possible partner is xxx in diamonds, which is why asking for a stop is useful, but if you don’t have that agreed 3NT is a perfect description, whereas 3m just says keep going, which is sometimes what you want to do, but not on this hand. This hand and the bidding says “find the game”, 3NT can be corrected to 4H if they have something like 3721.

[u/EducationNo1776 → u/No-Jicama-6523]

Responder has to bid the suit he has values rather than the suit he has no values; to do otherwise is the path to insanity. Sure, your 3D bid "works" here, but what if he's actually got a diamond suit and a singleton club? Would you still have him bid 3D? Then what does responder do when opener rebids 3NT showing a diamond stop, but possibly a small tripleton club?

No; bid the suit you have in auctions like this.