[whereagles]

Consider this auction in sayc or 2/1:

1♦ 2♣
2♦

Suppose responder wants to make a forcing raise of diamonds, or make a forcing bid with clubs. Not playing 3rd suit forcing, he doesn't have any choice but to "invent" a suit and hope for the best. With 3rd suit forcing, he can bid 2♥:

1♦ 2♣
2♦ 2♥

Now suppose opener has hearts, 11-14 hcp. He bids a natural 3♥

1♦ 2♣
2♦ 2♥
3♥

Now responder has, say, Kx AQxx xx AKxxx and is stuck for a bid. He would like to support hearts below game, but has no means of doing it in a way that will be clear to opener.

This can be fixed in 3 ways:

1. Keep 3♥ as natural, and have responder bid artificially now:
1♦ 2♣
2♦ 2♥
3♥ 3♠ = HEART raise, slammish
.....4♣ = club 1-suiter, slammish
.....4♦ = diamond raise, slammish

2. Make 2NT rebid as showing hearts. The 2NT isn't needed as natural because opener cannot have a balanced hand (he'd have bid 1♦-2♣-2NT or opened 1NT)
1♦ 2♣
2♦ 2♥
2NT = 4 hearts, 11-14. Now responder can bid 3H with a slammish hand

3. Play 1♦-2♣ as game forcing. This requires playing 1♦-3♣ as invitational and will force responder to bid 1♦-2NT with some club hands that are unsuitable for NT play. But then you'll have simplicity:
1♦ 2♣
2♦ 2♥ = natural. 3♥ by opener now shows a good raise of hearts.

Which of these solutions would you prefer? Or do you prefer something else?

[NickToll]

Years ago I read somewhere about a Lebensohl-like 2♥ rebid by responder in this sequence, showing a game-forcing hand with clubs and hearts OR a minimum 2♣ response; opener is compelled to 2♠, and now responder shows a minimum hand with 2NT, 3♣ or 3♦ (natural and invitational) or forces to game with any rebid from 3♥ on, showing hearts as well.

Playing this style, a direct 2NT, 3♣ or 3♦ by responder is natural and forcing; on the other hand, he is expected to bid a 4card major over 1♦ instead of a 5card club suit if he's not strong enough for game.

By the way, the same trick can be used by opener after 1♦-2♣; he can go through this kind of 2♥ with any minimum hand including only 4 diamonds (with 5, rebid 2♦).

[EricK]

Either make 2♣ GF or use 2♠ as support of ♥.

Eric

[HeartA]

I don't see any problem here if you play 2/1 gf.

[Chamaco]

Playing Precision with nebulous 1 diamond (bal 13-15, or <16 with 4+ D), I play that

a. 1D-3C is the invitational club 1 suiter
so that

b. 1D-2C can be invitational only if semi balanced: basically, 2C and 3C rebid is GF (cannot be NF otherwise responder would bid 3C right away) and the only NF rebid is 2NT.

c. With 5C + 4cM and invitational values, I bid 1M in response to 1D and then use XYZ.


I believe this scheme is playable also using better minor in a 2/1 framework.

[whereagles]

Well, perhaps this is a non-problem. Playing 3rd suit forcing with option 1, if it goes

1♦ 2♣
2♦ 2♥
3♥

Responder already knows a lot about opener: he has 54 diam/heart and 11-14 points. Maybe there's no need for a forcing heart raise, since responder can just blast 4NT with a heart fit and good hand. If responder is really in doubt, he can still use the vacant 3♠, which in principle asks for a spade stop, and support hearts later.

1♦ 2♣
2♦ 2♥
3♥ 3♠
3NT 4♥ <-- since resp wasn't interested in the spade stop, and didn't bid 4♥ directly, this auction must show a slam try in hearts.

Note: usually 1♦-2♣ is not a game force, even in 2/1. You can define it as such, but will lead to other problems.

[HeartA]

Even if you play SAYC and 1D-2C is not game forcing, 1D-2C-2D-2H(!!) is good enough for game forcing. So any auction below game after that shows slam interest.