BBO Discussion Forums: Major Mistake - BBO Discussion Forums

Jump to content

  • 3 Pages +
  • 1
  • 2
  • 3
  • You cannot start a new topic
  • You cannot reply to this topic

Major Mistake Finding a minor fit

#41 User is offline   mikl_plkcc 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 298
  • Joined: 2008-November-20
  • Gender:Male
  • Interests:sailing, bridge

Posted 2021-October-01, 12:57

What does 3 mean here? Is it GF? (I play it as GF)
0

#42 User is offline   Winstonm 

  • PipPipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 16,405
  • Joined: 2005-January-08
  • Gender:Male
  • Location:Tulsa, Oklahoma
  • Interests:Art, music

Posted 2021-October-01, 17:04

3S traditionally shows 16-18 and is non-forcing
"Injustice anywhere is a threat to justice everywhere." Black Lives Matter.
0

#43 User is offline   Gilithin 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 278
  • Joined: 2014-November-13
  • Gender:Male

Posted 2021-October-02, 07:07

View Postmikl_plkcc, on 2021-October-01, 12:57, said:

What does 3 mean here? Is it GF? (I play it as GF)

It is an important part of approach forcing bidding principles for raises such as this to show an invitational hand. As Winston write, 16-18 is the traditional range but in modern bidding, a good 18 will typically force to game so 16-bad18 is more precise. That said, it depends on how you organise your responses, since not all pairs respond equally and pairs also vary somewhat in how wide they allow their invites to be. The important part is that it is invitational absent special agreements; the rest you can adjust and apply to the specific system.
0

#44 User is offline   Douglas43 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 388
  • Joined: 2020-May-11
  • Gender:Male
  • Location:Isle of Man
  • Interests:Walking, boring my wife with bridge stories

Posted 2021-October-02, 09:04

View PostGilithin, on 2021-October-02, 07:07, said:

It is an important part of approach forcing bidding principles for raises such as this to show an invitational hand. As Winston write, 16-18 is the traditional range but in modern bidding, a good 18 will typically force to game so 16-bad18 is more precise. That said, it depends on how you organise your responses, since not all pairs respond equally and pairs also vary somewhat in how wide they allow their invites to be. The important part is that it is invitational absent special agreements; the rest you can adjust and apply to the specific system.


I too would see it as invitational, but tend to focus on Losing Trick Count (6 losers) rather than hcp.
0

#45 User is offline   Gilithin 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 278
  • Joined: 2014-November-13
  • Gender:Male

Posted 2021-October-02, 21:49

View PostDouglas43, on 2021-October-02, 09:04, said:

I too would see it as invitational, but tend to focus on Losing Trick Count (6 losers) rather than hcp.

When Winston and I talk about 16-18 in a context such as this, we are not talking about hcp so much as a combination of honour values and distributional values. I really didn't think it was necessary to mention it in this forum but...

The most common way of making such a combination is TP, which uses standard 4321 Milton Work plus 5 for a void, 3 for a singleton and 1 for a doubleton. Some older texts will use a different way of evaluating shortage: trump length - length of shortage. Many modern schemes will use 4.5, 3, 1.5 as the AKQ values for the hcp portion of the evaluation. In many of these evaluation methods, the values are equivalent enough (or can be made so through some simple maths) that the 16-18 will still be representative of an invitational hand.

LTC is a scheme that uses AKQ values of 3, 3 and 3 with VSD values of 9, 6 and 3. A 6 loser hand in this context is 18 points. The Modern LTC is a scheme that uses AKQ values of 4.5, 3 and 1.5 with VSD values of 9/4.5/1.5. 6 losers is again 18 points. There are plenty of other alternatives too - Zar Points is one of the more recent ones. To scale the hcp portion of ZP to regular points you multiply by 0.75. The distributional part is more difficult to convert - the simplest way is to subtract ~7 after the x0.75 scalar, which is not perfect but does give a more or less comparable figure. The OP North hand is 32 ZP, which gives an equivalent evaluation of ~17. This is a mild undervaluation, primarily due to the way the distributional conversion works. For comparison the LTC value is 18 (invite) and the MLTC value is 21 (game). As for Milton, the antiquated method gives 17 (invite), the traditional TP valuation is 18 (borderline invite/game) and the modern TP value is 19 (game).

And there are plenty of other methods that can be brought to bear, particularly if you want to produce less accurate results. It is irrelevant - Winston uses an evaluation scheme where the hand is an invite; I use a scheme where the hand is a game force....but we both understand what the bids mean. And they do not mean to look only at your hcp and ignore everything else.
0

#46 User is offline   pescetom 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 4,574
  • Joined: 2014-February-18
  • Gender:Male
  • Location:Italy

Posted 2021-October-03, 11:37

View PostGilithin, on 2021-October-02, 21:49, said:

LTC is a scheme that uses AKQ values of 3, 3 and 3 with VSD values of 9, 6 and 3. A 6 loser hand in this context is 18 points. The Modern LTC is a scheme that uses AKQ values of 4.5, 3 and 1.5 with VSD values of 9/4.5/1.5. 6 losers is again 18 points.

Please can you explain the meaning of VSD and what the three values refer to (or provide a link) ?
0

#47 User is offline   nullve 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 1,831
  • Joined: 2014-April-08
  • Gender:Male
  • Location:Norway
  • Interests:partscores

Posted 2021-October-03, 12:44

View Postpescetom, on 2021-October-03, 11:37, said:

Please can you explain the meaning of VSD and what the three values refer to (or provide a link) ?

V = void
S = singleton
D = doubleton

So simple LTC is to equivalent to a point count method where

A = 3
K at least doubleton = 3
Q at least third = 3
doubleton = 3
singleton = 6
void = 9

Must be good!
2

#48 User is offline   Douglas43 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 388
  • Joined: 2020-May-11
  • Gender:Male
  • Location:Isle of Man
  • Interests:Walking, boring my wife with bridge stories

Posted 2021-October-03, 14:42

View PostGilithin, on 2021-October-02, 21:49, said:

When Winston and I talk about 16-18 in a context such as this, we are not talking about hcp so much as a combination of honour values and distributional values. I really didn't think it was necessary to mention it in this forum but...

The most common way of making such a combination is TP, which uses standard 4321 Milton Work plus 5 for a void, 3 for a singleton and 1 for a doubleton. Some older texts will use a different way of evaluating shortage: trump length - length of shortage. Many modern schemes will use 4.5, 3, 1.5 as the AKQ values for the hcp portion of the evaluation. In many of these evaluation methods, the values are equivalent enough (or can be made so through some simple maths) that the 16-18 will still be representative of an invitational hand.

LTC is a scheme that uses AKQ values of 3, 3 and 3 with VSD values of 9, 6 and 3. A 6 loser hand in this context is 18 points. The Modern LTC is a scheme that uses AKQ values of 4.5, 3 and 1.5 with VSD values of 9/4.5/1.5. 6 losers is again 18 points. There are plenty of other alternatives too - Zar Points is one of the more recent ones. To scale the hcp portion of ZP to regular points you multiply by 0.75. The distributional part is more difficult to convert - the simplest way is to subtract ~7 after the x0.75 scalar, which is not perfect but does give a more or less comparable figure. The OP North hand is 32 ZP, which gives an equivalent evaluation of ~17. This is a mild undervaluation, primarily due to the way the distributional conversion works. For comparison the LTC value is 18 (invite) and the MLTC value is 21 (game). As for Milton, the antiquated method gives 17 (invite), the traditional TP valuation is 18 (borderline invite/game) and the modern TP value is 19 (game).

And there are plenty of other methods that can be brought to bear, particularly if you want to produce less accurate results. It is irrelevant - Winston uses an evaluation scheme where the hand is an invite; I use a scheme where the hand is a game force....but we both understand what the bids mean. And they do not mean to look only at your hcp and ignore everything else.


Thanks Glithin, and sorry the "hcp" was lazy typing. I've never really got into the "add points" methods of valuation suit contracts, and tend to count points only when looking at no-trumps, using LTC with a trump fit. So when I see a point count I tend to assume hcp without even thinking about it. Should have engaged brain! Posted Image
0

#49 User is offline   mikl_plkcc 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 298
  • Joined: 2008-November-20
  • Gender:Male
  • Interests:sailing, bridge

Posted 2021-October-04, 07:53

View PostWinstonm, on 2021-October-01, 17:04, said:

3S traditionally shows 16-18 and is non-forcing

So what's the forcing bid here?
0

#50 User is offline   mycroft 

  • Secretary Bird
  • PipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 6,058
  • Joined: 2003-July-12
  • Gender:Male
  • Location:Calgary, Canada

Posted 2021-October-04, 08:23

4 would be useful with that shape. 4 shows a hand stronger than 3, but not strong enough to open 2. Otherwise, a reverse or jump shift. Yes, sometimes you have to fake one. Luckily in this case, you can go back to spades ASAP and get the point across.
When I go to sea, don't fear for me, Fear For The Storm -- Birdie and the Swansong (tSCoSI)
0

#51 User is offline   Gilithin 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 278
  • Joined: 2014-November-13
  • Gender:Male

Posted 2021-October-04, 09:10

View Postmikl_plkcc, on 2021-October-04, 07:53, said:

So what's the forcing bid here?

With a shortage, splinter. Without a shortage, raise the major to 4. If neither of those look right, make a temporising forcing call (reverse or jump shift) and show support later.
0

#52 User is offline   Winstonm 

  • PipPipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 16,405
  • Joined: 2005-January-08
  • Gender:Male
  • Location:Tulsa, Oklahoma
  • Interests:Art, music

Posted 2021-October-04, 10:43

View Postmikl_plkcc, on 2021-October-04, 07:53, said:

So what's the forcing bid here?

Forcing or forcing raise?

Forcing raises are splinter and 4 of the opened minor.
"Injustice anywhere is a threat to justice everywhere." Black Lives Matter.
0

Share this topic:


  • 3 Pages +
  • 1
  • 2
  • 3
  • You cannot start a new topic
  • You cannot reply to this topic

1 User(s) are reading this topic
0 members, 1 guests, 0 anonymous users