Vulnerable at IMPS

[EricK]

It is well known that at IMPS one should bid games more aggressively when vulnerable.

 

This means that in vulnerable game auctions one or other of the players' bids must have a different range to what it would if non-vulnerable.

 

In Auctions like 1NT 3NT it is clear (isn't it?) that responder will have a lower lower limit for the 3NT raise than he would if non-vulnerable. But in an auction like

 

1♥ 1♠

2♦ 3♥ (Inv)

4♥

 

I can see three possibilities:

 

1. reponder invites on exactly the same hands he would when non-vulnerable and opener accepts more often

2. responder invites with a weaker hands than he would non-vulnerable (and bids game directly with the upper range of non-v invite) and opener accepts on exactly the same hands he would when non-vulnerable

3. a mixture of the above i.e. repsonder invites slightly more often and opener accepts slightly more often.

 

The same applies to all invitational auctions. So, in general, which method is best? Strangely enough, I have never seen this discussed in any books or heard of any partnership agreements on this topic. Yet if the partners are not on the same wavelength I can imagine responder inviting on a lower range (because we're vulnerable) and opener accepting on a lower range (because we're vulnerable) and so getting to vulnerable games which are well below the theoretical lower limit.

 

My hunch is that 2. is optimal (i.e. the person making the invite adjusts their range, their partner accepts or declines in the same fashion whatever the vulnerability), but I would be interested in other people's opinions.

 

Eric

[Guest Jlall]

Excellent post.

 

This is actually more widely discussed than you think. Some say agressive invites, solid accepting, some say the opposite.

 

Solid invites and agressive accepting is a good strategy (especially at MP) because you will play 1N or 2M OR 3N or 4M more often but not usually 2N or 3M (death contracts in uncontested auctions) and makes sense to me. The other case can also be argued (and i'll let others do it). Or you can play like meckwell, agressive invites, agressive accepts, good luck partner :) lol

[EricK]

Excellent post.

 

This is actually more widely discussed than you think. Some say agressive invites, solid accepting, some say the opposite.

 

Solid invites and agressive accepting is a good strategy (especially at MP) because you will play 1N or 2M OR 3N or 4M more often but not usually 2N or 3M (death contracts in uncontested auctions) and makes sense to me. The other case can also be argued (and i'll let others do it). Or you can play like meckwell, agressive invites, agressive accepts, good luck partner :) lol

At MP there is no advantage to bidding vulnerable games compared with non-vulnerable games so ones strategy should be the same at any vulnerability (when you are bidding to make at any rate).

 

But at IMPS, even playing solid invites/aggressive acceptances still leaves the question open as to whether, when vulnerable, one should make less solid invites or more aggressive acceptances.

 

Now it seems even clearer that the inviter should adjust his range - there is less scope for the partner (who already accepts often) to accept even more often!

 

Eric

[mikestar]

Excellent question.

 

Solid invites and agressive acceptances is undoutably correct at matchpoints at any vulnerability.

 

At IMPS vulnerable, however solid invites and agressive acceptances makes the example auction

 

1H-1S-2D-3H

 

forcing when vulnerable! Opener passes NV when only when dead minimum, so if he is more agressive vul, he will never pass.

 

Another good question is how much lighter the games should be. Jeff Rubens in his excellent The Secrets of Winning Bridge suggests 1 point. I suspect many modern players would bid a vulnerable game at IMPS 2 points lighter than NV--in that case, perhaps the optimum is for each partner to "borrow" a point.

 

Perhaps this "borrowing" should apply to one level openings vulnerable at IMPs?

[Free]

I usually play semi-solid invites, semi-solid accepts ;) So invite with a little less than normal, but also accept with a little less than normal. This keeps the balance, and if one player for some reason wants to be in a very sharp game, he can accept/invite with light hands as well.

[inquiry]

I play solid accepts, light invites. Here is the reason why, if I have a "solid invite" and we are vulnerable, I simply bid the game vul. That is, I am not willing to "risk" being short of game when I think we might have a shot opposite even the "right" minimum. Since I am jumping to game on the close hands, my invites tend to be ligher than normal (since I bid game on the "big invites"). This has the effect of making my invites lighter than normal (on average). So of course, the net effect is that partner should never accept with a minimum (hoping for the perfect fit), and should be careful with slightly more than minimum but bland distribution when we are vul.

[hotShot]

I don't think it is a good strategie, to change the point ranges of the bids.

 

To make game with minimum HCP you need perfect fit or some distribution.

 

What I do vulnerable at IMPs is to give my distribution a little more weight.

 

Arguments to upgrade my hand are for example:

• A short suit and an extra trump
  
• A "long" solid side suit
  
• If it's likely to have a double fit
  
• Opponents bid suggests well placed values
  
• Indication of "right" values e.g. aces in p short suits, help in his long suits
  

[MickyB]

Another good question is how much lighter the games should be. Jeff Rubens in his excellent The Secrets of Winning Bridge suggests 1 point. I suspect many modern players would bid a vulnerable game at IMPS 2 points lighter than NV--in that case, perhaps the optimum is for each partner to "borrow" a point.

No way it should be 2 points lighter. Thomas Andrew's research can be read here; His double dummy analysis showed that, using the fifths count (4 - 2.8 - 1.8 - 1 - 0.4), 3NT will make >50% of the time with 24.4 points or more, and >40% of the time with 23.8 or more.

[pclayton]

There was a thread on this a month ago with regards to 8 point invites in response to a 15-17 NT. Good reading.

 

I'm still in the solid invite / accept with almost anything camp even at IMPs. The problem with the opposite method is frequently you'll get to a hopeless game, down several, which tends to distort the IMP odds.

[Finch]

The "solid invite, accept light" approach seems to be fairly standard... except that in some auctions it can't apply. Thinking about my approach to total points scoring (where the odds on a vul game are even more extreme than at IMPS):

 

I keep my 1NT opening bids unchanged, invite (and bid game) slightly lighter, accept slightly lighter. If you invite very light you play in hopeless 2NT contracts too often. If you keep your invites solid you miss some playable games. I upgrade 4-4 in the majors and a 17-count more often.

 

I bid game as responder after opener's jump rebid more often (e.g. 1C-1S-3C or 1C-1S-2NT).

 

After a 1NT rebid systemically responder with a 5-card major can make a "light invite". I do this far more often than at pairs where I'd usually just pass 1NT.

 

I raise a 1-major response to the 3-level slightly lighter.

 

I rarely make a 3-card invite of partner's opening bid, tending just to bid game more often. When I do, opener needs a solid acceptance to bid game.

 

As responder to an overcall my raises are unchanged, but I make slightly lighter game tries as the overcaller.

 

Sometimes you have a hand where you know if partner has the right cards you are making game, but you can't find out. At matchpoints you might pass since the right cards are not sufficiently likely. At total points you just bid game and hope.

 

I keep responder's 2NT bids up to strength in an uncontested auction. Auctions such as 1H-1S-2D-2NT-3NT get doubled when they are going off.

[inquiry]

Well I have tried all permuatations, from invite and accepts both light (don't do that... lol), to normal invites, light accepts, and what I currently play, light invites, normal accepts.

 

Here is why I changed... I find that most of the time I am looking at a hand that is close between invite or bid game that when I am vulnerable, I simply bid the game. This is true rather or not I am opener on auctions like...

 

1H-2H

?

 

Where I press to game with most good 15/16 point and some 14 hcp hands when vul (I will not be balanced), or as responder where I hold like a balanced 9 and partner opens 1NT (my NT range is 14-16, lower this to most balanced 8's if yours is stronger).

 

So if I am willing to leap willynilly to game when it is close (as responder or opener), this naturally lead to the a lowering of the stregnth for an invite. Do I end up in 3H down one when I issue a light invite after 1H-2H where others might stop safely in 2H? Sure. But I also get to 4H where others are lanquishing in 2H.

 

I think, either way (normal invite, light accepts; or light invites, normal accepts) will work. But ask yourself, do you find yourself pressing to game on some light hands without inviting? I can't help myself, so this is why I do it "backwards".

 

Let's assume an auction 1S-P-2S you are vulnerable at imps, which of these hands will you leap to game on.

[hv=s=sjt98xxhak9dakctx]133|100|one[/hv]

[hv=s=sjt98xxhak9dakctx]133|100|one[/hv]

[hv=s=sjt98xxhak9dakctx]133|100|one[/hv]

[hv=s=sjt98xxhak9dakctx]133|100|one[/hv]

 

I think the answer is (assuming you play normal 1S-2S) you will bid or force to game on most of these hands. How much less do you need to invite (or how much more to force to game)?

[pclayton]

#1 and #4 are game bids (jeez, especially 4; looks pretty slammish even). #2 and 3 are game invites. SSGT on 2, LSGT on 3. 3 is a great example of a hand that could easily go down 2 or 3 (hopefully not doubled!) in 4 opposite the wrong hand.

[Guest Jlall]

i still like stretch to invite stretch to bid game :P

[HeartA]

I will bid game on all of the four hands. With #4, I might bid 3H (slam try). If pd bid 4S, I would try 5C. If pd bid 3S, I bid 4.

[Fluffy]

I think that vulnerable game thing is overrated, in the end guessing on the right moment is what will matter the most, I mean, any judgement you can apply is gonna work better than looking at vulnerability.

[mila85]

In a lot of sequences is one of partners a 'boss.'

 

1nt-p-2nt-p

?

Responder is a boss here. I opened and I described my hand very well. I accept with maximum and pass with minimum. No problem.

 

1s-p-2s-p

?

Opener is a boss. I use 3cdh as invit. Partner with minimal hand bid 3s with maximum 4s. With avarage hand must downgrade or upgrade - he knows how the hands go together.

Opener can bid more agressive vul. at imp but it's only his problem.

 

p-p-4s

We don't have an agreement how strong 4s shoud be. Opener is a boss here. His partner is well described by initial pass.

 

.....

[sceptic]

interesting, I wonder if Fred can add a feature to make all games played optinal,

 

i.e. all vul, no one vul, EW or NS permenantly one or the other so people can practice at the tables, still maintaining randon deals but just allowing us to set the vulnerability in the main lounge or at certain tourneys i.e. vunerable tourneys etc

[inquiry]

I think that vulnerable game thing is overrated, in the end guessing on the right moment is what will matter the most, I mean, any judgement you can apply is gonna work better than looking at vulnerability.

Give a talk to your dad.... at imps, part of my judgement, is how close I am to game and when to push and when not too. I find it amazing you ignore condition of contest when bidding.

[han]

I think that this whole value-invite is overrated too, especially if partner's strength is almost known, like after a 1NT opening or rebid. However, if you can make a descriptive invite, that's much more valuable, and in that case I wouldn't hesitate to make a light invite.

 

So for the auction 1NT-2NT-3NT, I think that the 2NT bid should be solid, and the accepting should be aggressive (e.g with 15-17 notrumps, accept with your average 16 counts). However, an invite like 1M-2M-3C (whatever it means) can be made much more aggressively, since partner will have a good idea of when to accept and when not to.

 

So when I can't give a good description of my hand, I usually guess (and guess a bit more aggressively when vulnerable at IMPs). When I can give a good description of my hand (especially when dummy!) I often invite, and I invite fairly light.

[Chamaco]

When we have a fit, I base my choice on LTC, not hcp count:

 

OPENER:

AFTER SINGLE RAISE (which promises about 9 losers)

- use judgment for game try with 5.5/6 losers and or 16-17 hcp

- bid game with 5.5 (use judgment) or 5 losers or 18+

- the choice also depends on the knowledge of whether the constructive raise were done with 3 trumps or with 4+ trumps

 

AFTER INVITATION

- refuses invitation with 7 losers;

- accepts invitation with 6 losers, uses judgment with 6,5 losers

- here too the choice depends from the promised length in the trump support

 

 

RESPONDER

 

- CONSTRUCTIVE raise with 9 losers

- INVITE: with 8 losers

- FORCE GAME with the tools available with 7 losers or less

- ALLOW FOR SLAM INVESTIGATION with 6 or less losers

----------------------------------------------------

 

In light of this, the 4 hands will be easy evaluated after 1S:2S, assuming 2S is 8-9/10, 9 losers (e.g. weaker raises would use 1NT forcing)

 

[hv=s=sjt98xxhak9dakctx]133|100|one[/hv]

6 losers hand,

Here I will make a game try, whatever GT you play

 

[hv=s=sjt98xxhak9dakctx]133|100|one[/hv]

Less than 6 losers hand (0.5 in S, 3H, 1D, 1+ in C), I use a game try

 

[hv=s=sjt98xxhak9dakctx]133|100|one[/hv]

little less than 5.5 losers, I bid game vulnerable, GT nonvuln.

Over the game try, with exactly 9 losers, responder will need some redeeming features in order to bid game (nice sidesuit, shortness, great support, etc), with 8.5 losers he'll bid game.

 

[hv=s=sjt98xxhak9dakctx]133|100|one[/hv]

Considering the extra length in spade and pard support, it is likely that we have no spades losers (1 loser only with 3-0 split and Q offside): in this case the hand is worth 4 losers.

I bid game.

[Cascade]

Another good question is how much lighter the games should be. Jeff Rubens in his excellent The Secrets of Winning Bridge suggests 1 point. I suspect many modern players would bid a vulnerable game at IMPS 2 points lighter than NV--in that case, perhaps the optimum is for each partner to "borrow" a point.

No way it should be 2 points lighter. Thomas Andrew's research can be read here; His double dummy analysis showed that, using the fifths count (4 - 2.8 - 1.8 - 1 - 0.4), 3NT will make >50% of the time with 24.4 points or more, and >40% of the time with 23.8 or more.

Even without this analysis it is easy to see that we are talking about a fraction of a trick which will correspond to only a fraction of a hcp.

 

At IMPs not vul games need about 45% and vul games need about 35% (we can do the exact math if you want).

 

The difference is around 10% of a trick.

 

With 40 hcp the each trick is worth roughly 3 hcp so the difference in our judgement needs to be about 30% of 1hcp.

 

One example will illustrate how fine this is:

 

If game needs us to get four tricks from this suit

 

AKQx

 

xxx

then

 

AKQ9

 

xxx

gives us a 47.7% chance and is enough not vulnerable

 

while

 

AKQ8

 

xxx

gives us a 38.6% chance and is enough vulnerable.

 

Basically the difference is very slight shift in attitude for both players when vulnerable.

[mikestar]

In suggesting that the modern trend might be 2 points lighter, I agree that this is actually too much. In fact I think the bast approach is something like this:

 

Always use the same basic numbers (points, losers Zarpoints, whatever) for invites, accepts, etc.

 

Now taking NV at IMPS as the norm where everthing is evaluated down the middle:

 

At matchpoints, be more distressed by your hand's flaws and less impressed by its good points.

 

Vul at IMP, be less distressed by your hand's flaws and more impressed with its good points.

 

Taking hand 3 as an example, I see three flaws--bad trumps, Qx, stiff A--and one good point--the excellent side suit. At matchpoinst I will invite but am worried about it and I wouldn't criticize someone who took a position and passed.

 

NV at Imps I invite will less worry. I would be deem pass over conservative and bidding game over agressive.

 

Vul at IMPs I invite with no worry at all and wouldn't criticize someone bidding game.

[Fluffy]

I think that vulnerable game thing is overrated, in the end guessing on the right moment is what will matter the most, I mean, any judgement you can apply is gonna work better than looking at vulnerability.

Give a talk to your dad.... at imps, part of my judgement, is how close I am to game and when to push and when not too. I find it amazing you ignore condition of contest when bidding.

For being agressive when vulnerable you don't win much, in average how much, 1 IMP/hand?, 1 IMP is really a lot in average, but on certain deals you come to be agreessive only because you are vulnerable, and play ridicoulous games you could avoid if you gave a deep thought to partner's expected holdings.

[luke warm]

most of you are better with the percentages than i am... i sort of understand fluffy's view, but i don't agree with it completely... taking wayne's numbers, ie playing a vulnerable game that has a 35% chance of making, it's pretty easy even for me to see that you make 7 times out of 20... that is 500 (game bonus) x 7=3500 extra points (not counting trick value)...

 

i think you'd have to be off one doubled a little more than 10 of the remaining 13 times to break even (that's 200 penalty plus the lost 140 for 3M you'd have made)... that assumes you're doubled on the other 13 hands... 'course i'm not a mathmatician so i'm not sure of that... someone is tho, i'll bet ;)

[flytoox]

I think this discussion of aggressive/solid invite/accept is not that meaningful without mentioning the hand evaluation and reevaluation. I think how to reevaluate your hand with the development of auction is more important than what discussed here. When you plan to bid a game and hope to make it, I think the vul. is not that important. It is a two side edge, if you make you win more, if you go down you lose more.

 

In Ben's frist example, pd's 2S didnt upgrade ur hand that much and you should invite I think(in 2/1 if u play 1M-2M as sound raise that is another story). However in Ben's fourth example, the hand becomes slammish after pd's raise.