Responder's 2nd bid
We are about to enter one of the most disputed arenas of bidding theory -- fast arrival vs. picture bids.
Let us begin by defining our scenarios, though. The most important case is the one in which opener still can have a minimum. That is, he has not jumped, or bid a new suit at the 3-level, or (if you play that variant) shown extras with a 2NT rebid. In other words, opener's 2nd bid was a lower suit than his opening major suit, or else a rebid of his opening suit.
In this situation, the main theoretical issue is to choose how responder will begin to limit his hand while still saving space for getting into the best suit, keeping in mind that opener can still have a good hand (i.e., preempting opener's descriptive plan can backfire).
These are the typical auctions that summon the opposing theoretical armies:
One thing that is readily apparent is that the bid-in-contention (as to whether this should be a Fast Arrival Situation or a Picture Bid Situation -- they will be defined in a moment) is always a game bid. In a 2/1 style, if you don't bid game as responder in your 2nd bid, your bid is game forcing -- what it shows is dependent on how your partnership deals with the auctions above.
Time to define our terms. A Fast Arrival style will use responder's game bids in the 2nd round as a way to limit the strength of the hand. In clear terms, it will depict a minimum game force, since a hand worth more than a minimum (enough to explore for slam) will try to conserve space by not jumping. A Picture Bid style will use responder's game bids in the 2nd round as a way to pinpoint specific features, that would be hard to convey otherwise. In the trump auctions, this is often trump strength (and lack of side controls), i.e., a hand which has some contributing features for a slam contract but no good way to show them cheaply.
In the 3NT example, this would be a very specific distribution and high card strength (for example, denying a 5th card in the club suit, showing a doubleton spade, and stoppers in the unbid suits in something like 16-17 high card points). Note that red suit length in this specific example can remain ambiguous inasmuch as opener has basically denied a 4-card side suit in a non-minimum hand.
So, what is recommended? Clarity in your partnership. Pick one style and apply it across the board, in all related auctions. My personal preference is the picture bid style, and I will present it in a bit more detail in the next blog entry of this series, but if one style were clearly superior to the other, it would have eliminated its competitor from common practice. This has not happened, so both styles are playable, and the important thing is for you and your partner to be on the same page.