[DinDIP]

As I like to open lighter than some with shapely hands with good suits, I also like to reverse a tad lighter than some. (Playing a weak notrump, I like to be able to reverse with something like Qx AQxx AKJxx xx instead of being forced to rebid 1N. If responder has a five count with five spades then 2♠ is almost certainly our best spot.) So, like Cascade, I play that responder's rebid of his major at the two level is NF, and doesn't promise more than five cards. That way we can play in 2M in a five-two fit when both opener and responder are minimum.

How to handle responder's GF hands with five+ cards in the major? A jump rebid shows a good 6+card suit (KQxxxx or better), and a double jump to game promises a (semi)solid suit with limited extras, often a seventh card in the suit (a picture jump). After
1♦ 1♠
2♥
responder could bid 4♠ with AQJTxx Kx Qx xxx or AKJTxxx Kx xx xx. Cascade's example (AKQT9xx Kx Kx xx) is too strong to jump to 4♠ so I'd bid 3♠ and then cue bid over 3N or 4♠.

When responder's suit is weaker or shorter (only five cards) he starts with 2N (Lebensohl) when holding a stopper in the fourth suit, three of opener's minor (with support) or 4SF without a stopper or support. If available, 4SF by responder after previously bidding 2N shows a five-card major while bidding the major shows six. When that distinction is not available 3M becomes ambiguous: it might only be a five-card suit.

In theory we play 3♠ as natural after opener shows extra shape (65+). After
1♦ 1♠
2♥ 3♣
3♥
3♠ is unclear. In theory, it suggests a weak seven-card suit (Kxxxxxx or the like that was not good enough to rebid 3♠ over 2♥) but that would mean responder has enough honours in the other suits to make his hand strong enough to GF -- which would make it more likely he'd support one of opener's suits (remember, responder didn't choose 2N as his rebid, which would have promised a stopper in clubs when he rebid spades). Maybe it should be a cue agreeing hearts, but that would be a memory strain, IMO.

[Zelandakh]

DinDIP, on 2015-August-04, 08:01, said:

How to handle responder's GF hands with five+ cards in the major? A jump rebid shows a good 6+card suit (KQxxxx or better), and a double jump to game promises a (semi)solid suit with limited extras, often a seventh card in the suit (a picture jump). After
1♦ 1♠
2♥

An alternative is to play transfer rebids. There are many such schemes possible - a simple one is for 2NT to be weak with clubs or GF with exactly 5 spades. 3♥ handles weak with spades and GF with 6+ spades. 3♠ is open - a logical meaning is 6+ spades without a club stopper. It would be wrong to suggest that you are not giving up quite a lot to get that non-forcing 2♠ rebid though. It works best in the context of Responder being limited; in the normal case it is not at all certain that the trade off is worth it.