[Yu18772]

I play it as very weak, but I know quite a few good players who play it as 8-11 HCP and singelton, 2NT singl ask. This seems to work pretty well.

[kenrexford]

awm, on 2011-April-01, 08:43, said:

I haven't found this to be true in practice. There is an issue that it can be hard to bid an invite opposite a super-max in standard bidding. What happens is that the auction starts 1♥-1♠ and then opener rebids at the three-level. This cramps your sequence somewhat, and responder's initial invite isn't enough to push past game even opposite 18-19. I think you can have much better auctions by starting 1♥-2♠ and letting opener take control via asking bids, rather than having to start 1♥-1♠-3x-3♠. This is item (3) on my original list. Note that a slam auction opposite a constructive (like 5-8) 2♠ bid is extremely rare.

For item (5), bidding over 1♥-2♠ invitational is really risky! You will get doubled basically any time the opening side doesn't have a spade fit (i.e. you know you're outgunned). Bidding over 1♥-2♠ constructive is a lot safer; opener basically needs extras to double you which is possible but not odds-on. So I think the invitational jump gets you a lot more numbers out of the opponents (or just shuts them out of the auction completely, if they are a bit more conservative).

For item (6), when I have an invitational hand with spades a lot of the time we are just going to play in 4♠. I would much rather have the auction 1♥-2♠-4♠ than a slower auction 1♥-1♠-2x-2♠-4♠, because opener's extra call in there is much more likely to help the opponents on lead than to help my side. Another one is 1♥-2♠-3NT where opener might have a rather stronger holding in one minor than the other, whereas 1♥-1♠-2x-2♠-3NT reveals which is the four-card side suit. The invitational spade hand is much more likely to land in 4♠ than the weak spade hand is.

Finally, there are occasionally constructive hands where your choice of contract depends on opener's second bid. For example say I have six lousy spades; I might be happy to pass after 1♥-1♠-2♥, but willing to rebid my spades after 1♥-1♠-2m. Or say I have 5125; I might want to rebid my spades after 1♥-1♠-2♦ but obviously not after 1♥-1♠-2♣ or 1♥-1♠-2♥. The intermediate hand is more likely to have a good spade suit (more overall strength), and what I lose by finding the "wrong" partial (i.e. say I have 6232 and partner has six hearts and I play in 2♠ instead of finding my 6-2 heart fit) I might get back by being a level lower (i.e. on the aforementioned hand without 2♠ INV I might bid 1♥-1♠-2♥-3♥, reaching the better strain but one level higher).

I agree with all of this. I suspect all of us who have played both ways for years would be able to augment this with even more reasons.

[Quantumcat]

Wow, I had never considered playing it as anything other than an invitational three-card raise in hearts...

[Fluffy]

I play it as invitational hand for hearts, based on shortness (2NT asks). It comes more or less as often as invitational in spades, and it is a bit more useful. I posted a hand long ago where it allowed us to find a very good slam finding that responder has the perfect hand.

[Quantumcat]

I can see that it would be kind of nice to have it as invitational in spades because that solves the problem of whether 1♥-1♠, 2♣-3♠ is invitational or forcing to game. Now it can be forcing to game which would make any good hand with 6+ spades easy to bid instead of being a bidding-forum problem. And the invitational-with-3 hearts hands are easy enough to bid, you change suit then jump to 3♥.