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Jacoby 2S/2NT variations On the cusp

#1 User is offline   mw64ahw 

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Posted 2021-September-05, 03:22

Struggling to decide whether this is a 50%er.
Does you Jacoby2/2NT variation make this any easier?

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#2 User is online   DavidKok 

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Posted 2021-September-05, 03:31

I'm sorry, what does 2 show? A weak jump shift in spades? A strong jump shift? In the former case you have a nice raise to 4, in the latter case stronger action is indicated.
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#3 User is offline   mw64ahw 

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Posted 2021-September-05, 03:39

View PostDavidKok, on 2021-September-05, 03:31, said:

I'm sorry, what does 2 show? A weak jump shift in spades? A strong jump shift? In the former case you have a nice raise to 4, in the latter case stronger action is indicated.

Jacoby2NT, but using 2 instead of 2NT for . The bid can be 2NT if that is your way
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#4 User is online   DavidKok 

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Posted 2021-September-05, 03:42

I don't play J2NT at all, I play De Maas.

Anyway, I assume you have a way to show shortness over a 2 Jacoby bid? I think it's a good idea to use that.
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#5 User is offline   mw64ahw 

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Posted 2021-September-05, 03:53

View PostDavidKok, on 2021-September-05, 03:42, said:

I don't play J2NT at all, I play De Maas.

Anyway, I assume you have a way to show shortness over a 2 Jacoby bid? I think it's a good idea to use that.

I'm experimenting with various approaches (also considering your De Mass approach). One version does have that option, the other doesn't need it, but in either case I'm still looking for the decision making required to move beyond 4 on these hands. I'm struggling with the revaluation on the hand combination and how to show it.
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#6 User is offline   mikeh 

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Posted 2021-September-05, 05:25

Im not sure what the point is: are you suggesting that we want to be in slam on this hand? And, if so, which slam?

6H by north is less than 50%, although only by a tiny amount. That makes it a bad slam, but hardly a terrible slam.

Its less than 50% because of the low but non-zero risk of a spade ruff even when the King is onside.opening leader holding x xx in the majors.

6N by south is purely 50%, so its one of those where the system getting you there or missing it is meaningless. Great for you for bidding it when the spade king is onside, terrible when it isnt.

I play different structures with my two main partners. Im not sure where wed end up since I think each player has some judgement calls to make, so if both are aggressive, wed get to 6H. If both are conservative, we miss it.
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#7 User is online   DavidKok 

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Posted 2021-September-05, 05:42

View Postmw64ahw, on 2021-September-05, 03:53, said:

I'm experimenting with various approaches (also considering your De Mass approach).
I should point out that it's called 'Maas' after Anton Maas, not Mass.
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#8 User is offline   mw64ahw 

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Posted 2021-September-05, 06:01

View PostDavidKok, on 2021-September-05, 05:42, said:

I should point out that it's called 'Maas' after Anton Maas, not Mass.

Auto spell check
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#9 User is offline   mw64ahw 

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Posted 2021-September-05, 06:06

View Postmikeh, on 2021-September-05, 05:25, said:

Im not sure what the point is: are you suggesting that we want to be in slam on this hand? And, if so, which slam?

6H by north is less than 50%, although only by a tiny amount. That makes it a bad slam, but hardly a terrible slam.

Its less than 50% because of the low but non-zero risk of a spade ruff even when the King is onside.opening leader holding x xx in the majors.

6N by south is purely 50%, so its one of those where the system getting you there or missing it is meaningless. Great for you for bidding it when the spade king is onside, terrible when it isnt.

I play different structures with my two main partners. Im not sure where wed end up since I think each player has some judgement calls to make, so if both are aggressive, wed get to 6H. If both are conservative, we miss it.

This one is a close call, but as it stands I end in 4 without a slam investigation. When its close to 50% I at least like to make the investigation. Im wondering if there is any scientific approach that at least gets you to the investigation stage.
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#10 User is offline   Gilithin 

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Posted 2021-September-05, 08:13

View Postmw64ahw, on 2021-September-05, 06:06, said:

This one is a close call, but as it stands I end in 4 without a slam investigation. When its close to 50% I at least like to make the investigation. Im wondering if there is any scientific approach that at least gets you to the investigation stage.

What do you mean by investigation stage? For me North shows a minimum with a singleton and South judges that that is not quite enough for slam. Is that an investigation or not? No idea. You only need to start checking for controls and key cards if you judge the hands to have enough for slam to be good absent the opps having 2 quick tricks.
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#11 User is offline   mw64ahw 

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Posted 2021-September-05, 09:28

View PostGilithin, on 2021-September-05, 08:13, said:

What do you mean by investigation stage? For me North shows a minimum with a singleton and South judges that that is not quite enough for slam. Is that an investigation or not? No idea. You only need to start checking for controls and key cards if you judge the hands to have enough for slam to be good absent the opps having 2 quick tricks.

Looking at it from a pure MLT basis North has ~7.25 MLT and is Min with 13/14 total points depending on whether you count both an honour adjustment & 'Quack' adjustment. (I count one or the other).
With standard revaluation for the long suit (+3) this becomes 17 total points with possible extra value for the Q & QJ opposite a 12/13+hcp for standard Jacoby 2NT.
Looking at South's hand we have 7MLT with 15hcp + 1 for the 'Quack' adjustment and a flat shape which can work well opposite an unbalanced hand.
So with 17/18 +16 total points i.e. 34 total points max. We are in borderline slam territory.
I'm not quite sure how to adjust North's MLT yet, but possibly half the point adjustment works giving 6.5. South has an intermediate hand with 3 keycards so I call that 6.5; again slam territory.
As mikeh points out its close to 50% for North, but there may be times when you want to make the call.
The issue for AI machine learning is finding a s set of constructs that convey this information so that we can proceed to (say) Italian Q bidding and continue/stop
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#12 User is online   Douglas43 

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Posted 2021-September-05, 09:55

4. For a slam to be good here I need as a minimum K, AK, A. If any of those cards is missing, I need A and K to compensate.
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#13 User is online   Douglas43 

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Posted 2021-September-05, 09:59

View Postmw64ahw, on 2021-September-05, 03:39, said:

Jacoby2NT, but using 2 instead of 2NT for . The bid can be 2NT if that is your way


If I used 2 for Jacoby I'd be worried about giving the opponents an opportunity to find a Spade sacrifice via a double. Presumably there is a benefit that you think makes it worth that risk, could you enlarge on it please?
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#14 User is online   Winstonm 

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Posted 2021-September-05, 10:08

View Postmw64ahw, on 2021-September-05, 03:22, said:

Struggling to decide whether this is a 50%er.
Does you Jacoby2/2NT variation make this any easier?

Spoiler



If I'm behind in the 4th quarter I probably want to bid slam. Otherwise, no. (Unless it makes, of course.) Posted Image As for team play, I really think the team parameters should be discussed prior to playing - as a team, are we OK with 50-50 small slams?
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#15 User is offline   akwoo 

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Posted 2021-September-05, 10:34

My favorite version is

1H - 2S (invitational+, 4+ hearts)
4H (minimum, 6 hearts) - P

Yes South has to take a long look to see what the odds are for a slam over the 4H bid, but I don't think they're very good unless you open very sound and hence have a sound definition of minimum. Without a ruffing value it's hard to count to 12 tricks.

As to why 2S instead of 2N, we've got a somewhat complicated structure after 2S that allows us to pack both the limit raise and the overstrength splinter in it. After 1H-2S-2N(nondistributional minimum), 3C asks partner for shortness, 3D shows the overstrength splinter, and 3H asks partner to pass. Needing to bid 1H-2N-3C-3S for the overstrength splinter just takes up too much room.

Yes it does give opps the possibility of doubling, but we really want the extra step.
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#16 User is offline   mikeh 

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Posted 2021-September-05, 10:42

View PostDouglas43, on 2021-September-05, 09:59, said:

If I used 2 for Jacoby I'd be worried about giving the opponents an opportunity to find a Spade sacrifice via a double. Presumably there is a benefit that you think makes it worth that risk, could you enlarge on it please?

Using 2S as J2N in support of hearts conserves bidding space, which is always a good idea in game+ situations.

It also allows 2N to be natural and forcing, which can be useful on occasion

The fear of allowing them to find spades is, in my experience with the method, not a serious problem.

Many good players bid over 1M (p) 2N on any good suit, without much regard to length or hand strength.

Surprisingly few pairs have an easy time doubling the interference, especially when red v white, but also at equal.

After all, 1H (p) 2N (3S)..they dont know I have, as I might, KQJ10x xxx xxx xx or KQJ10xxx x xxxx x, and they do know that they have at least nine hearts and game values or better.

So letting me double 2S rather than bid 3S is not optimal but, in the real world, my bidding 3S is more likely to disrupt their auction than would my double of 2S
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#17 User is offline   Gilithin 

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Posted 2021-September-05, 11:23

View PostDouglas43, on 2021-September-05, 09:59, said:

If I used 2 for Jacoby I'd be worried about giving the opponents an opportunity to find a Spade sacrifice via a double. Presumably there is a benefit that you think makes it worth that risk, could you enlarge on it please?

Some very good players, including for example Fred Gitelman, like to use a 2NT response naturally. This means that 2/1 auctions become purer and that has advantages down the line, particularly for game vs slam scenarios. If you do this then the easiest adjustment is to use 1 - 2 and 1 - 3 as your GF raises.
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#18 User is offline   mw64ahw 

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Posted 2021-September-05, 11:49

View PostDouglas43, on 2021-September-05, 09:59, said:

If I used 2 for Jacoby I'd be worried about giving the opponents an opportunity to find a Spade sacrifice via a double. Presumably there is a benefit that you think makes it worth that risk, could you enlarge on it please?

I'm aware of the opportunity for doubling. I've used 2 in this case as one of the versions I'm looking at needs the extra step to be symetric.
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#19 User is online   Winstonm 

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Posted 2021-September-05, 12:20

View PostGilithin, on 2021-September-05, 11:23, said:

Some very good players, including for example Fred Gitelman, like to use a 2NT response naturally. This means that 2/1 auctions become purer and that has advantages down the line, particularly for game vs slam scenarios. If you do this then the easiest adjustment is to use 1 - 2 and 1 - 3 as your GF raises.


You can also use Bergen as an either/or bid. 3C is either limit or game force. 3D relays.
Bergen 3D becomes the mixed raise.
If you also eliminate the weak Bergen raise of 3M you can use that bid for a strong raise with no slam interest.

This frees 2N/3N as natural.
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#20 User is online   Douglas43 

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Posted 2021-September-06, 06:08

View PostGilithin, on 2021-September-05, 11:23, said:

Some very good players, including for example Fred Gitelman, like to use a 2NT response naturally. This means that 2/1 auctions become purer and that has advantages down the line, particularly for game vs slam scenarios. If you do this then the easiest adjustment is to use 1 - 2 and 1 - 3 as your GF raises.


Thanks for that and to others who have replied on my question. It's interesting to see different emphasis players put on having Jacoby / natural 2NT / natural jump shift available
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