[straube]

I'm looking for help understanding pass double inversion. It's a method after strong 1C interference at high levels after a GF has been established. So let's say the bidding goes 1C-1S (4D) Suppose here that 1S showed a GF balanced hand or m/m hand and 4D interference is natural.

PDI is...

dbl-shows 3-suiter
suit-single-suiter
P-requests dbl
.....dbl-a hand that wouldn't pull a penalty dbl
..........P-penalty dbl
..........suit-2 suited (that suit and another)

I've been wondering why this method is better and why it only applies to higher level interference (like 3S or higher). I'm guessing that it doesn't apply at lower levels because at lower levels opener stands a better chance of bidding two suits naturally. At 3H, for instance, opener can bid 3S and then 4m or 4S. So at lower levels, p=takeout or directionless and suits are single or two-suited. Right so far?

So after 1C-1S (3H)-P P dbl P 3S would show a takeout of hearts (p/d not inverted)

but after

1C-1S (3S)-P P dbl P

3N would show minors
4C-H/C
4D-H/D

[lowerline]

This can be played any time you are in a forcing pass situation. So after 1♣ (p) 1♠ (3♥) p (p) dbl (p) 3♠ would show spades and a minor and still give partner the option to bid 3NT.

Steven

[slyq]

far as i can see the advantage is if you want to slam try
e.g 1c 2h 3d 4h pass here tells p to x then when 4h x comes back to the 1c bidder
and he bids 4s this is a slam try in spades as opposed to a direct 4s over 4h
it allows the 1c bidder to take more control of the auction by alowing him 2 ways to bid a suit or raise p it also allows the posibility of plying in 4nt
when a direct 4nt would be blackwood via the double it becomes to play e.g. with the above hand you hold ax aq xx akqxxxxx you pass then over x bid 4nt
if you can see anything else to it please post as i am interested

[straube]

lowerline, on Mar 24 2010, 05:14 AM, said:

This can be played any time you are in a forcing pass situation. So after 1♣ (p) 1♠ (3♥) p (p) dbl (p) 3♠ would show spades and a minor and still give partner the option to bid 3NT.

Steven

At what bid do you invert the meanings of pass and double? I think 3S makes more sense personally.

Btw, it seems like opener's bids after partner doubles back in should be...

S1-two lowest
S2-highest and lowest
S3-two highest

So if you played PDI for 3H, then 3S by opener (after dbl) would show both minors

[akhare]

straube, on Mar 24 2010, 09:04 AM, said:

At what bid do you invert the meanings of pass and double?  I think 3S makes more sense personally.

Btw, it seems like opener's bids after partner doubles back in should be...

S1-two lowest
S2-highest and lowest
S3-two highest

So if you played PDI for 3H, then 3S by opener (after dbl) would show both minors

[Edit -- I am beginning to wonder if the two suiters should be shown immediately because the bidding could be at the 5 level]

Actually, playing the scheme you suggested, won't it work starting 3♣ onwards?

1♣ - (P) - GF - (3♣) :

P: Penalty or very two suited
X: Three suited takeout
3X: Natural
4C: Majors no slam interest?

[Edit]

It might be better to show the two suited hands with M+m immediately over the 3♣ bid:

4♣: Majors
4♦: D+H
4♥: D+S


After the X:

P: Penalty
3D: H+D
3H: S+D
3S: Probably H+C, COG (vul. not right)
3N: Probably S+C, COG (vul. not right)
4C: Majors, H longer or equal, slam interest
4D: Majors, S longer or equal, slam interest
4H/4S: Slam interest?


1♣ - (P) - GF - (3[CD]) :

P: Penalty or very two suited
X: Three suited takeout
3X: Natural
4C: Majors no slam interest?

After the X:

P: Penalty
3H: H+C
3S: S+C
3N: Probably M+D, COG (vul. not right)
4C: Majors, H longer or equal, slam interest
4D: Majors, S longer or equal, slam interest
4H/4S: Slam interest?

[straube]

akhare, on Mar 24 2010, 10:37 AM, said:

straube, on Mar 24 2010, 09:04 AM, said:

At what bid do you invert the meanings of pass and double?  I think 3S makes more sense personally.

Btw, it seems like opener's bids after partner doubles back in should be...

S1-two lowest
S2-highest and lowest
S3-two highest

So if you played PDI for 3H, then 3S by opener (after dbl) would show both minors

[Edit -- I am beginning to wonder if the two suiters should be shown immediately because the bidding could be at the 5 level]

Actually, playing the scheme you suggested, won't it work starting 3♣ onwards?

1♣ - (P) - GF - (3♣) :

P: Penalty or very two suited
X: Three suited takeout
3X: Natural
4C: Majors no slam interest?

[Edit]

It might be better to show the two suited hands with M+m immediately over the 3♣ bid:

4♣: Majors
4♦: D+H
4♥: D+S


After the X:

P: Penalty
3D: H+D
3H: S+D
3S: Probably H+C, COG (vul. not right)
3N: Probably S+C, COG (vul. not right)
4C: Majors, H longer or equal, slam interest
4D: Majors, S longer or equal, slam interest
4H/4S: Slam interest?


1♣ - (P) - GF - (3[CD]) :

P: Penalty or very two suited
X: Three suited takeout
3X: Natural
4C: Majors no slam interest?

After the X:

P: Penalty
3H: H+C
3S: S+C
3N: Probably M+D, COG (vul. not right)
4C: Majors, H longer or equal, slam interest
4D: Majors, S longer or equal, slam interest
4H/4S: Slam interest?

I think the disadvantage of PDI at lower levels is that it prevents responder from showing 2-suited hands (as well as 3-suited hands). At lower levels we have more room to sort this stuff out.

Say it goes 1C-1D GF (3C)

opener can bid any suit here and rebid any other suit or the same suit. He can pass and pull a dbl indicating 3 places to play. Or he can dbl. But his actions if PDI not on give responder more room to maneuver. For instance, after a penalty dbl, responder can show a 1-suiter OR a 2-suiter (but probably not a 3-suiter). Also 3N is in the picture.

Your use of 4C etc to show 2-suiters robs responder of the ability to bid 3N or to show a single-suiter.

[akhare]

straube, on Mar 24 2010, 11:15 AM, said:

I think the disadvantage of PDI at lower levels is that it prevents responder from showing 2-suited hands (as well as 3-suited hands). At lower levels we have more room to sort this stuff out.

Say it goes 1C-1D GF (3C)

opener can bid any suit here and rebid any other suit or the same suit. He can pass and pull a dbl indicating 3 places to play. Or he can dbl. But his actions if PDI not on give responder more room to maneuver. For instance, after a penalty dbl, responder can show a 1-suiter OR a 2-suiter (but probably not a 3-suiter). Also 3N is in the picture.

Your use of 4C etc to show 2-suiters robs responder of the ability to bid 3N or to show a single-suiter.

I think the question of whether opener show two suited hands immediately is slightly different from the the double / P inversion question.

The way I see it, the most cogent argument in favour of the inversion is that we are already in a GF and there's no compelling reason to penalize them immediately. Note that the P only "requests" a X as opposed to demanding it, i.e., responder may freely introduce a new suit or simply bid 3N with the right hand.

Regarding showing two suited hands immediately, the primary loss is the ability to play in 3N. I think the inability to show single suited hands is less important because given that opener will have 2 cards or fewer support in most cases.

[straube]

akhare said:

The way I see it, the most cogent argument in favour of the inversion is that we are already in a GF and there's no compelling reason to penalize them immediately. Note that the P only "requests" a X as opposed to demanding it, i.e., responder may freely introduce a new suit or simply bid 3N with the right hand.

Responder may introduce a suit, but the point is that responder is not so free and is comparatively cramped for showing his hand. To make it more clear, let's suppose 1C (P) 1DGF (4D) P (P) ?

4H by responder would have to be taken as a single-suit. Responder might have a 2-suiter and guess that 4H is playable, but he might guess wrong. Plus disaster if opener has S and C and the partnership plays now in a 5-1 fit when a 5-5 fit was available. Certainly if he's strong enough he could cue bid 5D (or 4N?) as two places to play, but sometimes he'll get too high. With most 2-suited hands, responder will dbl back in and hope that opener has a good penalty pass or hope that opener will bid out showing his 2 suits and thus finding a fit.

Anyway, that's the downside of PDI and that's why it is only played at higher levels.

[akhare]

straube, on Mar 24 2010, 12:27 PM, said:

Responder may introduce a suit, but the point is that responder is not so free and is comparatively cramped for showing his hand. To make it more clear, let's suppose 1C (P) 1DGF (4D) P (P) ?

Isn't this an argument in favour of the inversion? I don't think that either method can really clearly win after a 4♦ interference, but I think the inversion allows the hand in the opener to better clarify the nature of the hand:

1C - 1D (GF) - (4D)

Without inversion:
=============
P: Forcing, may be three or two suited
X: Penalty
4H/4S: Single suited, TP

Responder's X: Two suited / takeout oriented
Responder's 4H/4S: Single suited

After responder's X:
===============
4H: Picking hearts in response to responder's TOX?
4S: Picking spades in response to responder's TOX?

As I see it, opener may have a very two suited hand or could be picking the a suit in a three suited hand.

With inversion:
===========

X: Takeout, emphazing majors
P: Request a X, either two suited OR penalty
4H/4S: Single suited, TP

Responder's X: Two suited / takeout oriented
Responder's 4H/4S: Single suited

After responder's X:
===============
P: Penalty
4H: Two suited with hearts
4S: Two suited with spades

[straube]

akhare said:

Isn't this an argument in favour of the inversion?

Yes. PDI at high levels is better.

akhare said:

With inversion:
===========

X: Takeout, emphazing majors
P: Request a X, either two suited OR penalty
4H/4S: Single suited, TP

I don't think that's quite right. See if opener has something like Ax AKQx xxx Axxx and the bidding goes 1C-1D (4D) he'll have to double with this hand for takeout. True, it's ugly (I made it ugly deliberately) but his next best choices are to pass and convert a double to penalty or to treat a 4/4 hand like a 2-suiter. It could be even worse, but the good news is that hands like this ought to be infrequent. Btw, 4N by opener directly would probably be to play.

After 1C-1D (3S) it's possible for opener to show all of his 2-suiters below game. After 1C-1D, (4D)-P P dbl P 4H would show hearts and another and responder's bid of 4S would be pass/correct. In fact, it's possible that responder might have something like A Kx xxxx Qxxxxx and have to pass 4H when the partnership has a 11 cd club fit available.

Such is life. But if responder has a slamming hand, he can cue bid to find opener's second suit.

So why might non-inverted be better at low levels? Because let's say the bidding went 1C-1D (3D). With Ax AKQx xxx Axxx opener passes and plans to accept a cooperative dbl by responder. If responder bids the expected 3S, opener bids 4D which says "I have a decision to make and I need your help. I plan to pass your next bid if it's an agreeable spot to play."
Responder might rebid 4S or he might surprise opener with a 4H bid. Opener passes either one.

[slyq]

not sure here but two factors to consider here the dynamics of doubling 4d and lower is quite different to game if you double game and it makes who cares but bringing bacck 4c or d x making is a lot more painfull normally 1c 1h 1s 3h x is t/o
and a pass encourages partner to x anyway though he will bid 3nt with a stop when he knows you are unlikely to have a penalty x ( because of his own reasonable hs) so inversion applies here any way to some extent though quite differently than over 4M + where you have to decide if to try the 5 level or opt for a power based penalty good luck

[lowerline]

straube, on Mar 24 2010, 09:04 AM, said:

lowerline, on Mar 24 2010, 05:14 AM, said:

This can be played any time you are in a forcing pass situation. So after 1♣ (p) 1♠ (3♥) p (p) dbl (p) 3♠ would show spades and a minor and still give partner the option to bid 3NT.

Steven

At what bid do you invert the meanings of pass and double? I think 3S makes more sense personally.

Btw, it seems like opener's bids after partner doubles back in should be...

S1-two lowest
S2-highest and lowest
S3-two highest

So if you played PDI for 3H, then 3S by opener (after dbl) would show both minors

As I said: anytime you are in a forcing pass situation. I don't see the benefit of having two sets of agreements where the level of the bidding determines the one you use...

Steven