BBO Discussion Forums: 好坏2n(原文转帖) - BBO Discussion Forums

Jump to content

Page 1 of 1
  • You cannot start a new topic
  • You cannot reply to this topic

好坏2n(原文转帖) 优秀约定叫

#1 User is offline   dvd 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 620
  • Joined: 2013-April-15

Posted 2013-August-28, 22:13

标 题: 关于好坏2NT讨论的汇总
本文摘自《水木清华BBS》,是讲师,cozofu,hbear和monk9等高手对“好坏2NT”约定的讨论。
================================================================================
摘自伯根叫牌百科全书

你 左手敌家 同伴 右手敌家
1D - 1H 1S
X* 2S 2NT -
?

你持:

A632 A74 A864 85

3C。同伴的2NT是好-坏2NT,你的支持性X并不影响同伴好-坏2NT的使用。

如果同伴持有:

8 J973 K5 QJT942

你的3C接力叫,就是终止在这个定约上的最好逻辑叫牌途径。

=================================================================================
讲师说:

我觉得这其实已经是现代桥牌中不可避免需要讨论的一个课题了,但是由于太过艰深,
目前问津者仍然不多。似乎有必要进行一定的研讨,欢迎大家发表意见,我只不过是
一知半解,需要大家集体智慧,因为其中需要讨论的内容确实太多。

我最初接触这个问题是在2001年国家队集训,当时张德生介绍这个约定叫,他说“如果
没有好坏2NT,就不会打牌了。”当时国家队中已经有人使用好坏2NT,但是也有人对这
个约定叫似乎完全不感兴趣。总的来说,好坏2NT是一个概念,需要同伴之间探讨的地方
非常多,缺乏讨论很容易引起同伴之间误会,这也是很多牌手不愿意去涉足的原因。

此后的两年中,我一直没有仔细研究过这个约定,和一些爱好理论的搭档如hbear,ljing,
cozofu等打牌的时候也从来没有实践过这个约定,但是在很多场合下我都深切体会到此约
定的用处。由于激烈竞叫是现代桥牌的主要特征,好坏2NT适用的场合非常之多,好处也
是相当明显的。

前天打完牌后和刘老师、吴老板、马老板、zyz,lzp等一起吃饭时讨论一个牌,叫牌进
程和前面我所贴《摘自》一文中进程完全相同。当时又引起我对好坏2NT的思考,后来同
ljing探讨,发现他也并不是很重视这个问题。至于教主,一向是采取敬而远之的态度。
虽然我忽然提出这个问题有点不揣冒昧,但是觉得在论坛上面讨论这样的问题实在是一
个大家交流和研究的好机会。

讲师收集的资料:
标 题: 伯根的原文(1)

如果考虑当代叫牌总体倾向,一个不可回避的事实是,叫牌越来越具有竞争性。

甚至于,一些初出道的新手,也喜欢“到我这儿”就或作弱二开叫,或做弱跳争叫,或
作持4张套的花色争叫,等等,让敌方牌手自己猜去!
  
因此,我们强烈地感觉到,需要拥有有效的反击武器!
  
利本索尔约定叫,就是七十年代发明的流行于世的反击武器之一:它是一个尝试对付敌
方干扰叫牌的极好的约定叫的例子。

利本索尔约定叫有一个特点,它放弃了2NT的自然叫品含义,而把它当作一个约定性逼叫
处理;并且我们通过2NT逼叫方式的这个媒介,可以显示我们持有一手强牌或一手弱牌的
牌情。利本索尔约定叫还可以用于敌方弱二开叫,同伴技术性加倍之后。

如果说利本索尔约定叫的这个观点昭示了一条原则,我们为什么又不可以利用约定性2NT
叫品,来限制这两种类型的叫牌过程呢?难道我们还有更多的机会,让同伴知道我们持
有一手好牌或一手坏牌的可能吗?

例如,当你面临如下叫牌过程,你是如何对付的呢?

同伴 右手敌家 你 左手敌家
1D 1S X 2S
3H PASS ?

你持有如下一手牌:

643 AT64 J7 A965

如果同伴持低限牌,例如:

K5 KQ75 A532 T72

3H定约对你方来说已是够高的了,你只有PASS。

但是,假如同伴是持更好的一手牌再叫3H的:

8 KQ93 KQT64 KT3

如果你PASS的话,你就将错过一个极好的4H成局定约了!

而另一种类型的问题,可能发生在如下叫牌过程之后:

同伴 右手敌家 你 左手敌家
1D 1H 1S 2H
3D - ?

你持一手大牌点与上面一手牌一样多的牌:

AT864 A73 J4 T94

3NT对你很有诱惑力,如果同伴是持如下一手牌,在敌方任何首攻之后即可摊牌:

Q5 94 AKQT72 A32

然而,假如同伴只是持如下一手牌,他仅仅是作出3D竞争性再叫(谁也不能责怪他),
因为只可能止于3D定约,你又怎么知道应当PASS呢:

Q3 92 KQT8762 AJ

在面临上面两种为难局面时,有没有解决办法呢?

当然有!你只需把利本索尔约定叫中的观念,移植到这里就可以解决了。

下面这个约定叫是在五年前,由一位芝加哥的专家牌手设计出来的,它一出世就赢得不
少追随者。它的基本想法是:你在持一手好牌时先叫出逼叫性2NT,同伴在一般情况下总
是先作出3C接力叫(这一点上与利本索尔约定叫相同);现在,你就可以标明你的好套
所在,并且还可以显示持有额外价值。这种2NT约定性逼叫的方式,可以称为“反式利本
索尔约定叫”(Reverse Lebensohl),因为在常用的利本索尔约定叫版本中,2NT约定
性逼叫,你首先是考虑持一手较弱牌情况下作出的。

然而采用“反式利本索尔约定叫”方式,你在持较弱的牌时就会发现,来自敌方的进一
步争叫将会使你方的竞叫变得困难;很可能会阻止你方在3阶水平上采用自然叫品阐明牌
情。

因此,与众不同,我们实际上定义的这个2NT约定性逼叫,仅在你持较弱的一手牌情况下
作出的,为竞争性叫牌,即持有简单加叫的实力,或 信 稍强一点的实力,具有花色再
叫的能力。既然敌方有可能进一步争叫,使我们失去3阶水平的配合叫牌机会,我们还不
如冒一点风险,把它处理为持较弱的一手牌。我们把这种2NT约定叫方式命名为“好-坏
2NT”(Good-Bad 2NT),你也不妨把它叫做“第三利本索尔约定叫”或“等效利本索尔
约定叫”。

为此,我们建立如下使用“好坏2NT”的规则:

1、发生的一个竞争性叫牌,都是在2阶水平上进行的(即右手敌家的开叫或争叫未到
2NT);

2、你右手敌家的叫牌(包括开叫和争叫)必须是一个花色叫牌,或是加倍,或是再加
倍,不得是PASS。如果这两个条件都兼而具备时,你在3阶水平的直接叫牌,就是承诺
了具有额定的价值(但不是逼叫性的)。而2NT叫牌则可能打算在任何一门花色上进行
竞争性叫牌的继续进行。虽然2NT叫牌者可能打算在任何一门花色上进行竞争性叫牌,
但是他也不可能有逆叫实力(因为你的2NT已否认持有额外的价值)。你的同伴通常被
迫作出3C接力叫,但是有时他也可以按照自己的意图作出其他的一个叫牌。例如,同伴
持:

A KJ96 KQJ643 52

当下面的叫牌过程之后:

左手敌家 同伴 右手敌家 你
2S X - 2NT
- ?

很清楚,同伴应当再叫3D,而非3C。因为他不可能担当起你有可能对3CPASS的风险(如
果你是持有C套弱牌的话)。再例如,同伴持:

864 KJ85 KT62 J5

在下面叫牌过程之后:

你 左手敌家 同伴 右手敌家
1D 1S X 2S
2NT - ?

同伴也应当再叫3D。因为,假设你是持有两套低花的话,他总是希望做D定约的,他在此
及时地向你显示D配合。

同样,当同伴持有一手好牌时,他必须不失时机地显示自己的好套或配合,而不能懒洋
洋地叫出3C接力叫。例如,在下面的叫牌过程之后:

你 左手敌家 同伴 右手敌家
1D - 1S 2H
2NT ?

如果同伴是持:

AKT63 93 KT4 K63

他应当扣叫3H!

如果同伴是持:

AT94 KQT 83 A643

他应当直接叫到3NT,只当你是按标准叫牌法方式再叫出3阶水平的低花情况一样,因
为,显然已经没有高花或低花成局定约的机会了。

在竞争性叫牌中,你持有可作好-坏2NT叫牌价值的一手牌的频率是很高的,所以,它对
你十分有帮助。但是,我们也发现,在满足前面我们规定的好-坏2NT叫牌的条件时,有
一种情况不可能使用好-坏2NT叫牌。例如,在下面的叫牌过程中:

同伴 右手敌家 你
1H 2D 2NT

你的2NT应叫必须是自然性的邀请!否则,你便没法处理如下一手牌:

643 AT KJ6 QT643

因此,我们不得不进一步提出不适合好-坏2NT叫牌要求的一览表——

1、当2NT必须是自然性的邀叫时;

2、当2NT很清楚地表明是特殊无将争叫时;

3、当敌我任一方开叫1NT时;

4、当低方开叫强1C时。

5、当敌我任一方弱二开叫时(不能紧接敌方弱二开叫之后作出好-坏2NT叫牌,而我方弱
二开叫之后则绝对禁止使用好-坏2NT叫牌);

6、当从逻辑上推断已不可能是好-坏2NT时(因为已确知敌方持有非常强的牌,或你已确
知你方持有非常弱的牌);

7、当敌方作出惩罚性加倍时;

8、当敌方使用一个2阶水平的约定性叫品来预先防御我们采用好-坏2NT叫牌时;

9、当我方花色开叫,紧接着又作出一个加叫(可能是扣叫,显示对同伴的花色配合)时
(因为配合已被发现,而且很容易区分邀叫与止叫);

10、当我方已经是在进行进局逼叫性叫牌进程时;

11、当我方已作出一个关煞性跳叫时。

注意,我们不使用好-坏2NT方式的理由,归纳起来,是属于以下两种:

A、如果我们已确切地知道这一副牌是“属于”敌方的,还是“属于”我方的了(第4、
6、10、11条);或

B、我们必然不能破已有的同伴间的协议(不管是约定性的,还是自然性的),而且它们
已经显现在叫牌之中了(第1、2、3、5、8、9)。当然,第3条和第5条,已经明显属于
“利本索尔约定叫”了。

还需要考虑的一个问题是:因为敌方在你作出“坏的”2NT叫牌之后的进一步争叫,可能
会使你失去在3阶水平显示花色叫牌空间;所以,你在作出“好-坏2NT”叫牌时,得预先
作出正确的决定,是否应当选择“好的”3阶水平花色叫牌。

例如,当你持:

64 AQJT74 92 T53

在叫牌过程:

左手敌家 同伴 右手敌家 你
1S 2D 2S ?

之后,你完全可以选择好-坏2NT叫牌。但是,如果左手敌家进一步叫出3S,你就不可能
在3阶水平上安全地作出H竞争性叫牌了。所以,权衡之下,现在你更应该选择“好的”
3H叫牌(而不是好-坏2NT)!因为这是值得显示的好套。

在我们进一步举例说明好-坏2NT叫牌之后,我们还得回答一些牌手可能早就想到的一个
问题——

好-坏2NT是百分之百的逼叫性约定叫吗?

我认为,既然同伴在作出好-坏2NT叫牌时,是考虑继续竞争,我 钊爸钗换故 不要PASS
为好。它当然是逼叫性的。然而,在某些极少有的场合下,还是有充分理由PASS的。所
以又不是百分之百逼叫性的。假设叫牌过程是这样一来进行的:

同伴 右手敌家 你 左手敌家
1C 1S - 2S
2NT* - ?

你凝视手中这样一手牌:

KJT8 8743 96542 —

同伴显然倾向于做C定约,因为——正如我们在建立“好-坏2NT”的规则时所说明的——
同伴不具备额外价值,如果你作出3C接力叫,同伴一定会PASS。当你反正要作为明手把
这破牌摊在桌上时,还不如让同伴作2NT这个更低一阶的定约。因而,你的PASS是言之有
理的。

再例如,你持:

KQT -- T8743 Q9642

在叫牌过程:

你 左手敌家 同伴 右手敌家
- - 1H 1S
X 2S 2NT -
?

之后,我总是选择PASS(即使有点紧张)。因为我可以假设,同伴可能无低花长套而要
再叫H(如果你作出3C接力叫的话)。而且可以想象,如果同伴持如下一手牌:

84 AKT874 AQ T73


做3H至少要被宕三(还可能被敌方加倍)。所以,我PASS之后同伴做2NT定约,至少可以
在比赛分制中得到一个平均分,免糟灭顶之灾。

但是,如果同伴持如下一手牌:84 AQJ74 2 KJ853

由于他还有C好套,他就会怨恨我了。我们在比赛分制中,2NT定约只能得到底分,冷落
了一个漂亮的4C定约。

==============================================================================
标 题: 伯根的原文(2)

现在,我们给出一些实例,来检测你所学的好-坏2NT知识。

1、

左手敌家 同伴 右手敌家 你
1S 2D 2S ?

你持:

A85 K63 Q843 874

3D。这是我们刚才提到的“好的”3阶加叫。如果你缺少一张HK,就可以叫出好-坏2NT。

2、

你 左手敌家 同伴 右手敌家
1D 1S - 2D
?

你持:J KT AKQJ742 643

2NT。你不用为持有这么坚固的D套担忧。但是既然第一轮同伴PASS,你不想过分鼓励同
伴把问题弄得复杂化。如果你还持有另一张A,你就可以加叫3D,期望同伴持如下一手牌
时叫出3NT:

K542 Q86 T6 J752

3、

你 左手敌家 同伴 右手敌家
1D 1S X 2S
?

你持:

J KT AKQJ742 643

3D。这一次,因为同伴作出了加倍,你不需要他还要持有另外的牌力就可能做成3NT定
约。同伴将自动3NT。

4、

左手敌家 同伴 右手敌家 你
1S X 2S ?

你持:

874 63 K54 QJT85

2NT。你想继续竞争下去,但又不想太鼓励同伴。

5、

你 左手敌家 同伴 右手敌家
1D - 2H 2S
?

你持:

63 A8 KQJ865 Q85

3D,而不是好-坏2NT!因为已建立起进局逼叫进程,好-坏2NT已不复存在。

6、

你 左手敌家 同伴 右手敌家
1D 1S 2D 2S
?
 
你持:

K63 A8 A943 Q875

你绝不能叫2NT!即使你已看到这手牌值得叫自然性的2NT——但是,此时叫出的2NT却是
好-坏2NT。所以只有PASS,同伴会清楚你这一手牌情的。

7、

你 左手敌家 同伴 右手敌家
1C 1S 1NT 2S
?

你持:

8 94 AJ52 AQT743

2NT。之后准备止叫于同伴的3C。同伴在第一轮应叫1NT这个事实,不会影响你这个决定。

8、

同伴 右手敌家 你 左手敌家
1D - 1NT X
- 2H ?

你持:82 74 A53 QJ9874

2NT。此后准备止叫于同伴接力叫的3C。同样地,与你第一轮的1NT应叫无关。

9、

你 左手敌家 同伴 右手敌家
1NT - 2D 2S
?

你持:85 AKT6 A74 KJ85

3H。即使你持低限开叫牌。在1NT开叫后不能使用好-坏2NT。

下面试一试你对同伴好-坏2NT之后的叫牌。

1、

同伴 右手敌家 你 左手敌家
1S - 1NT 2H
2NT - ?

你持:T AJ743 98542 K7

3C。同伴持有S和一门低花,如果他的低花是C,你希望他持有5张套。如果他下一轮转换
至D,你就可以作出D加叫

2、

同伴 右手敌家 你 左手敌家
1D 1S - 2S
2NT - ?

你持:

Q8543 87432 95 J

3D。而不是3C!不管同伴是否持有2套低花或是只有一套D,你都希望他以开叫花色作为
将牌。这是没有办法的事,两害之中取其轻。

3、

你 左手敌家 同伴 右手敌家
1D - 1H 1S
X* 2S 2NT -
?

你持:

A632 A74 A864 85

3C。同伴的2NT是好-坏2NT,你的支持性X并不影响同伴好-坏2NT的使用。

如果同伴持有:

8 J973 K5 QJT942

你的3C接力叫,就是终止在这个定约上的最好逻辑叫牌途径。

4、

同伴 右手敌家 你 左手敌家
1C - 1S 2H
2NT - ?

你持:

KQJT74 94 Q874 8

3S。只当你是对同伴3C再叫之后的叫牌。你的3S再叫不是逼叫性的。因为你要是需要作
出逼叫的话,你可以3H扣叫,而你这手牌不够扣叫资格。

5、

同伴 右手敌家 你 左手敌家
1H - 2H 2S
2NT - ?

你持:

J74 Q106 A94 K852

3NT。在你方花色开叫,紧接着一个加叫之后,好-坏2NT已经失效,同伴的2NT是询问短
套。

6、

你 左手敌家 同伴 右手敌家
1H 1S X -
2H X 2NT -
?

你持:

A63 KQT743 86 A5

3C。记住,同伴的好-坏2NT可能发生在他的右手敌家的任何2阶水平叫牌,包括除惩罚性
加倍外的其他加倍之后(和再加倍之后)。同伴的右手敌家的这个加倍,在此叫牌过程
中是技术性的。因此同伴的好-坏2NT仍然有效,他可能持:

K5 -- J7432 QJT843

7、

同伴 右手敌家 你 左手敌家
1S 2H X XX
2NT - ?

你持:

62 A5 KJT974 J42

3D。同伴的2NT仍然是好-坏2NT,但是,你该坚持选D为将牌,否则你叫出3C接力叫,同
伴可能PASS,这是你不愿看到的。

8、

同伴 右手敌家 你 左手敌家
1H 1S - 2S
2NT - ?

你持:

J7432 J53 84 J63

3C。不管同伴此后怎么打算,你都希望他做定约。

最后,我们讨论一下,在同伴3阶水平叫牌替代好-坏2NT之后的叫牌。

1、

同伴 右手敌家 你 左手敌家
1D 1H 1S 2H
3D - ?

你持:

A8743 K5 Q3 J642

3NT。同伴未再叫好-坏2NT,而是再叫出3D,他就保证了一手好牌!然而,采用标准叫牌
法的牌手在此就得颇费猜测了。

2、

同伴 右手敌家 你 左手敌家
1H 1S X 2S
3C - ?

你持:

853 QJ 10973 KQ64

4H!一旦你从同伴的3C再叫得知,他不仅仅是在作竞争性叫牌,你就感到叫出4H总是正
确的。否则,在同伴持如下一手牌时:

T7 AK963 Q AJT54

你就会冷落了这个漂亮的成局定约。

3、

你 左手敌家 同伴 右手敌家
1H 1S 1NT -
2H 2S 3H -
?

你持:

8 AQJT74 93 KQT6

4H。在同伴的第一轮的1NT应叫后,你还不敢有进局的奢望;然而当同伴第二轮并没有叫
出好-坏2NT,而是叫出鼓励性的3H加叫,你就知道,值得进局了。

4、

右手敌家 你 左手敌家 同伴
1S X 2S 3H
3S ?

你持:

84 AQ6 AT64 AT52

加倍。因为同伴已越过了好-坏2NT而叫出3H,这就宣告了他持有的一手牌的实力,所以
你可以继续竞争。在拥有3.5个快速赢墩、3张H和2张S的情况下,加倍是最灵活的叫品。
同伴应当知道该怎样更好地处理。

===============================================================================
标 题: 伯根的原文(3)


关于好-坏2NT的问题

1、当叫牌还在一阶水平上进行时,可以使用好-坏2NT吗?

[解答]

有时也可以。试想,在如下叫牌进程之后,你怎样能够更好地把你持的下面两手牌区分
开来呢?

你 左手敌家 同伴 右手敌家
1D - 1H 1S  
?

(1)、6 82 KQJT742 AQ5

(2)、84 K7 AKJT74 AQ5

虽然,持以上两手牌时,我感到都可以跳到3阶上去;但是,我们总是喜欢在持第一手牌
时叫出关煞性、竞争性的3D,而在第二手牌时叫出示强的3D。因为,假设关煞性跳叫是
尽可能地给敌方留下较少的叫牌空间,所以在一阶水平上跳叫使用“好-坏2NT”时,是
采用的“反式好-坏2NT”的方式。

因此,你在持(1)者一手“较弱的”牌时,你应该再叫3D;而在持“较强的”(2)这一手
牌时,你却应该再叫出“好的”2NT来!

下面,给出一些应用“反式好-坏2NT”的例子。

1、

你 左手敌家 同伴 右手敌家
1H - 1S X
?

你持如下一手牌时,叫3H

8 QT97532 AKJT 8

你持如下一手牌时,再叫“反式好-坏2NT”:

A— AQJT74 AJ7 62

2、

你 左手敌家 同伴 右手敌家
1C - - 1H
?

你持如下一手牌时,再叫3C

A7 94 T5 AQJ9742

你持如下一手牌时,再叫“反式好-坏2NT”:

A8 A73 8 AKJT742

2、虽然“反式好-坏2NT”的确显得明智,特别是对我们这些喜欢关煞叫的牌手来说。但
是,这又意味着,我们放弃了跳叫2NT显示持18—19点的自然含义。那么,这种情况下
我们又该怎么办呢?

[解答]

这个问题是理论性的,而非实用性的。因为在竞叫过程中,你持自然性再叫2NT的牌发生
的可能性是很低的。但是,这也是可以处理的。

在叫牌过程:

你 左手敌家 同伴 右手敌家
1C - 1H 1S
?

之后,我持如下一手牌,总是跳叫3NT:

AQ8 A7 K53 AQT74

而在持如下一手牌时,总是再叫2D

A74 A6 A742 KQJT

而在持如下一手牌时,总是再叫出支持性加倍:

A6 K82 KJ5 AK864

换句话说,你通常总可以发现合乎逻辑的其它叫品。

如果我持:

AJ92 A7 J64 AKJ8

我当然也会因为不能叫出自然性2NT或惩罚性加倍而感到不高兴。因此,持这一手牌,你
必须在跃上3NT或陷阱式PASS之间做一选择。这显得有点极端。

但是在实践叫牌中,你通常总是会在1S争叫之后,找到一个合适的叫品的。如果你PASS,
同伴也总是会在持短时试图做平衡叫牌的。

3、必定存在另外一些情况,我们喜欢叫出自然性2NT,但在“好-坏2NT”方式下却不能
叫。你能给我一些帮助吗?

[解答]

这事儿当然会发生,但是,如果你善于从对立面的角度来考虑这问题,也许事情就会容
易解决一些。毕竟,如果你拿到这样一手牌:

KJ9 J73 9542 K97

在叫牌过程:

左手敌家 同伴 右手敌家 你
2S X - ?

之后,你又不可以叫出自然的非逼叫2NT,大概你就没有什么希望作其它叫牌了,因为,
你是采用利本索尔约定叫方式的。

所以,如果你持:

94 AQ6 KJT8 8543

在叫牌过程:

左手敌家 同伴 右手敌家 你
1H X 2H ?

之后,你应以3C取代2NT(因此时2NT不是自然性的,而是好-坏2NT)。

如果你持:

AQ T8764 Q5 K654

在叫牌过程:

同伴 右手敌家 你 左手敌家
1C - 1H 1S
- 2S ?

之后,你应以3C取代2NT。

诸如此类。记住,这些3阶水平的叫品都是邀叫,类似自然2NT

4、当我们在敌方2阶水平的干扰叫牌之后,选择了3阶跳叫,有无任何特殊情况发生?

[解答]

正如你期待的,这样使我们对同一叫品简单地获得两种叫牌方式,同时,得以区别“较
弱的”和“较强的”不同牌情。

在叫牌过程:

你 左手敌家 同伴 右手敌家
1S - 1NT 2C
?

之后,你持如下一手“较强的”牌时,跳叫3H(逼叫性):

AK854 AQJ93 A7 8

而在持而在持下面一手“较弱的”牌时,则先叫好-坏2NT,再叫出3S来:

KQT9743 9 AK9 64

但是,无论你采用哪一种方式,当同伴持如下一手牌时,都不会丢失高花成局定约机会:

9 KJ6 KJ643 T742

同样地,在叫牌过程:

你 左手敌家 同伴 右手敌家
1S - 1NT 2C
?

之后,如果你持这样一手“较强的”牌时:

AQJT74 AQ9 A6 74 你就可以跳3S。


=============================================================================
讲师收集的资料:

标 题: 拉里·科恩的介绍
摘自《叫或不叫——总墩数定律》,内容较少。

好坏2NT

要清晰地说明这个十分有用的观念,最好的办法是举一个实际的牌例,比方说,你持下
列的牌,开叫1H:

X X
A K X X X
X
K J 10 X X

同伴答叫1NT,右敌却插叫2S。虽然你只有 11大牌点,却极想叫出3C。因为你知道敌方
至少有8张的黑桃(同伴答叫1NT,表示没有4张黑桃),你不能让他们主打形势大好的
2S。

可是,这时你如再叫3C,就会发生你俩叫牌结构中的一个重大问题。因为你是居於开叫
人自由再叫的位置,如果立即叫出,那表示你持有17大牌点的实力,而你实际上只有11
大点,相差不可以道里计。那麽怎样才能向同伴表明你只是竞叫,或是你的确有自由再
叫的实力呢?这种情况,在实战中,屡见不鲜,是一个不容忽视的问题,而你则陷入又
想竞叫,又怕同伴误会的两难困境!

为解决这个问题,我们建议此时你应叫好坏2NT。这是「雷本索尔叫法(Lebensohl
Convention)」的变种,可以让你十分有效地在三线进行竞叫,其规定为:

在竞叫的情况中,当右敌作任何二线超叫之时,开叫人叫出2NT,并非自然叫,而是告诉
同伴,他意欲在三线进行竞叫,并要求同伴无条件答叫3C,以後开叫人再叫他的第二门
花色。

如果开叫人的第二门花色正好是梅花,他就派司。如果他不经过2NT立即叫出第二门花
色,就表示他持有自由再叫的实力。

兹举数例,说明好坏2NT的运用:

例一、

西 北 东 你
1H 2D 2H ?

你持:

K X X
A X X
Q 10 9 X
X X X

此时,你可以直接加叫3D,同伴就知道你是有相当实力的三线加叫,如果你只持:

X X X
A X X
Q 10 X X
X X X

你应先叫2NT,要求同伴无条件叫3C,你再叫3D,同伴就知道你是低限的支持。

例二、

西 北 东 你
    1H
2C — 2S ?

你持:

X
A K Q X X
A K J X X
X X

你可以直接叫3D,同伴就知道你是有自由再叫的实力,但如你只持:

X
A X X X X
A K J X X
X X

你就应先叫2NT,於同伴无条件叫3C之後,再叫3D。

例三、

西 北 东 你
      1H
1S 1NT 2S ?

你持:

X X
A K J 10 X X X
K X X
X

你应先叫2NT,於同伴无条件叫3C之後,再叫3H。同伴就会知道你只有低限的开叫力量。
如果你持:

A X
A K J 10 X X X
K X X
X

你就直接叫3H。

例四、

西 北 东 你
      1D
1S X 2S ?

你持:

X X
K J 10 X
A K X X X
X X

依照正常叫法,你不宜自由再叫3H,然而你又不愿意让敌方主打很便宜的2S合约,此处
你仍然可以施展好坏2NT,先叫2NT,等同伴无条件叫3C之後,再叫3H,同伴就知道你是
起码开叫了。

当然,有时也会有混淆的情况发生,到底你真的是要打2NT,或是迫同伴无条件叫3C,不
大容易立即断定,不过,我们发现,还是有若干情况可以立即断定是真的或不是真的要
打2NT。一对有志向上的桥伴,对这一方面应该多作讨论,以免误会。在《柏根氏精进叫
法》书中,举出许多相当明显的情况,可供参考。那是:

——当极明显的是不寻常2NT时。

——当任何一方曾经开叫过1NT时。

——当敌方以强梅花开叫时。

——当敌方已叫出处罚赌倍时。

——当我方已叫出迫叫成局的叫品时。

即使你没有作很精细的探讨,也仍然可以用常识来判断。比方说:同伴开叫1D,敌方超
叫1H,你持:

AXXX
AX
XXX
AJXX

你叫「赌倍(负性)」,敌方加叫2H,同伴叫2NT(好坏),他的真正意思是要再叫3C
或3D,所以此时(你持有这么强的牌!)你绝不可墨守成规,照他的意思叫出3C!因为
万一他真的持有梅花花色,他将派司,那岂不大糟其糕!因此你唯一的叫法是示叫敌方
的花色3H!!同伴马上就知道你是一手强牌。

再看下面也是一个十分明显的情况:

你持:

AX
AXXX
J10XX
XXX

你 左敌 同伴 右敌
    1D 1S
X(负性) 2S 3H —
?

你作负性赌倍後,同伴立即自由再叫3H,而不叫好坏2NT,你就可以轻松地加叫到4H。假
如同伴只持:

KX
KQXX
KQXX
JXX

他会先叫2NT,你就再叫3D(不应答叫3C,因为如要你选择低花,你也是叫3D),假使同
伴又叫3H,你就放心派司,不怕会丢掉一局。

使用这种好坏2NT叫法,可以於敌方叫出大好的二线合约之後,和他们在三线上从事有效
的竞叫。你不用耽心你方会失去真正要打的2NT,这种情况,实在少之又少,所以我们认

定:利用2NT来通知同伴你的真正实力,所产生的重大效用,实远胜於真正可以主打2NT,
所得到的利益。


===============================================================================
hbear的个人观点:
发信人: hbear (huge bear), 信区: Bridge
标 题: 关于2NT在不同场合下的运用


2NT作为一个约定叫牌来使用,在现代桥牌中常常能够见到

从好坏2NT或类似好坏2NT的用法考虑,是否选用这样的约定叫
首要的问题就是:是否在一些场合下2NT用作约定叫要远优于作为自然叫或者其它用法?
显而易见,这样答案是肯定的,在某些场合下因为牌力的含混给叫牌信息带来的破坏远远
要超过丧失2NT自然叫的影响;
其次的问题就是:究竟在多少场合下,值得使用2NT?也就是好坏2NT使用频度的问题,
这个问题才是讨论或者合理使用好坏2NT的关键所在

换一个角度考虑,对于不同的前期形势,使用2NT的价值会有很大的差别
lebensohl之所以是一个优秀、普及很高的约定叫是因为有一个很大的牌力空间
需要区别(比如2M-X之后,如果没有lebensohl,一个叫品的牌力可能在0-11之间)

对于自然叫牌来说,开叫范围很宽,开叫人在面临可能需要使用好坏2NT的时候
牌力的变化会比较大,大致在12-17左右,因此选择使用好坏2NT的频度也应该比较高

对于限制性比较强的体系,比如精确,同样的形势下,牌力大致在11+-15之间

一些额外牌型显著的15点甚至可以作一些超过3阶意愿花色的叫牌
因此选择使用好坏2NT的频度相应就小很多;
对于应叫人,因为叫牌起点要比自然法高一些,相应的牌力范围也有所缩小

当然,不否认在限制性体系中好坏2NT仍然有用武之地
但是好坏2NT的一个特点就是需要有\"充分的准备\",能垒比较高:)
对于不准备打上好几年以上的搭档,似乎风险还高于收益

====================================================================
发信人: cozofu (一一), 信区: Bridge
标 题: 好坏2NT


好坏2NT的基本出发点是为了解决如下的叫牌难题,
在竞争性序列下, 对方在二阶的争叫或者加叫迫使你在三阶
出新花, 叫原花, 或者加叫同伴时, 你无法向同伴用一个叫品
来表达清楚你的打牌实力, 而2NT通常不会是理想定约,
你能够加叫2NT的牌通常可以通过加倍或者在对方花色太强时pass来表示,
因此有必要引入好坏2NT的概念, 这样叫2NT要求同伴接力到3C,
对于开叫人, 2NT显示D/H/S邀叫实力的牌, 有额外实力, 或者
C套上逼叫进局的牌. 对于应叫人, 2NT显示C套竞争性的非逼叫牌或者
邀叫的牌.

下面文章我将举例说明如何运用好坏2NT.


叫牌序列:
1D p 1H 2S
?

Sx HAKx DKQJxxx CJxxx
直接叫3H, 你无法用支持性加倍, 这牌适合进攻, 因此你叫3H.
希望同伴会处理4-3将牌.

Sx HKJxx DAQJxx CQxx
同样, 你应该叫3H, 竞争性.

Sxx HAKxx DAQJxx CKx,
叫2NT, 同伴接力3C之后叫3H, 完成对你牌力的描述, 即原本你
想1-3跳叫的牌.

Sx HAKx DAKJxx CQxxx,
也还是叫2NT, 以后在3C后面叫3H, 表示你有1-3跳叫的实力, 这里你无法区分
3张还是4张加叫.

SAK Hxx DAKJxxx CKxx,
直接跳3NT.

Sxx HAK DAKQxxx CQJx
叫3S, 显示逼叫到局的牌, D单套强牌, 询问黑桃挡张.

Sxx HAKxx DAKJxx CKx,
叫4H. 3S是错误的.

Sx HAKxx DAKJxxx CKx,
叫4D: 显示H配合, D6张, 单张S的牌.

Sxx HAKxx DAKQJxx Cx
叫4C, H配合, 精确的2-4-6-1牌.

Sxx HA DAKxxx CAxxxx
叫3C, 这里3C显示C-D双套5-5的牌, 建设性.

Sxx Hx DAKxxx CKJxxx
pass, 你无法在这里显示最弱的双低花.

Sx HAx DAKJxxx CKxxx
叫2NT, 3C之后叫3D, 显示你具有1-3跳叫的牌力.

Sxx Hxx DKQJTxx CAQx,
直接叫3D.

Sxx Hx DAKQJx CAKJxx
叫2NT, 之后叫3S, 显示双低花5-5, 进局逼叫, 没有 谔 挡张.

SAx Hx DAKJxx CAQJxx
叫2NT, 然后3NT, 显示双低花5-5, 有 谔 挡张.

这样非以上牌型的准均形牌应该在有额外实力时加倍, 或者在黑桃很好时pass.

下面再介绍应叫人在开叫人2NT之后的处理方式.

叫牌序列:
1D p 1H 2S
2N p ?
你的3C是绝对逼叫的, 开叫人有义务澄清自己的持牌类型.
因此多数时候你可以简单叫3C, 在开叫人叫清楚自己的牌之后,
你可以决定下一步怎么办.

拿了Sxx HQJTxxx DKx Cxxx, 你应该叫3H, 显示弱牌, h基本能
独立做将.

拿了好的5张红心或者一般的6张H, 你可以叫3D, 显示弱牌,
这样同伴有三张时依然可以加叫你到3H或者4H.

任何高于3H的花色叫牌应该是D套配合的好牌, 显示单缺.
4H显示坚固H, 温和满贯兴趣.

应叫人的好坏2NT:
1D p 1H 2S
p p ?

Sx HKQJxxx DQxx Cxxx,
叫3H: 显示红心长套, 竞争性.

Sxx HKJxx Dx CAJxxxx
叫2NT, pass 同伴的3C

Sxx HAQJxxx Dx CKxxx
叫2NT然后3H, 1-3跳叫的牌, 邀请.

Sx HAKxxx Dxx CAJxxx,
叫3C, 进局逼叫.

Sx HAKxx DKxx Cxxxxx,
叫3D, 希望同伴会打4-3配合.

SJx HAxxx DQxx CKJx
加倍, 你很欢迎同伴拿4张时罚放!

Sx HAxxx DAKxxx CQxx,
叫2NT, 然后叫3S, 显示D套好配, 没有S挡张的牌.

SAx HAxxx DAKxxx Cxx,
叫2NT, 然后叫3NT, 显示D套好配, 有 谔 挡张的牌.

Sx HAKJxxx Dxxx CAxx,
叫3S, 显示H6张套, 进局逼叫的牌.

Sx HAKxxx DKxxx Cxxx,
叫2NT, 然后叫3D, 显示1-3跳叫的牌, 邀请.

=====================================
讲师对好坏2NT与坏好2NT的解释:

miles认为,当你持有竞叫实力的牌时,敌方往往更容易继续竞叫,这样你叫2NT之后
同伴就不知道你的持牌类型,从而不知道是否应该继续采取行动,而你通常也不能再
进行竞争。而如果你持有邀叫实力的牌时,敌人继续竞叫的可能性降低,你可以先叫
2NT再显示你的牌情。这也就是使用坏-好2NT而不是好-坏2NT的原因。

=====================================

我的读后感:

伯根、科恩使用好坏2NT,但研究表明,cozofu介绍的坏好2NT是目前该领域的主流。


================================================================================
0

#2 User is offline   dvd 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 620
  • Joined: 2013-April-15

Posted 2013-August-28, 22:15

(接1楼原文的英文资料)
标 题: John Hoffman的Good-Bad 2NT


Good/Bad 2NT

By John Hoffman

We thank John Hoffman (hoffman) for allowing us to publish this article. He
has been playing online for many years and was awarded the Angelfish two
years ago for his work teaching others and his ethics and etiquette at the
table. You can find more of his articles at his website: members.home.net/
leilas/hoffman/bridge.htm

SUMMARY

This is a description of the Good/Bad 2NT convention as played in my
partnership with Leila Sink. This convention uses 2NT in competitive
situations as an artificial bid to show a hand that is weaker than bidding
directly at the three level. The intended audience for this article is
expert players in steady partnerships.

INTRODUCTION

Consider this contested auction:

1D-1S-Dbl-2S
?

You hold one of these hands that should compete respectively to 3H, 3D, 3C:

84 A742 AK53 Q97

8 K7 AKT9543 Q97

84 4 AKT53 AQ974

Or you hold one of these hands that should invite to game:

8 AJ42 AK532 Q97

8 A7 AKT9543 K97

84 4 AKQ53 AQJ74

As you can see, it is hard to make affordable natural bids that clearly
distinguish between competitive and invitational values in this situation.

Now try another one:

1H-1S-2C-2S
?

Suppose the bidder would like to bid a suit at the 3 level. This time, the
auction is already game invitational for the bidder’s side. So the issue
is how to show whether the hand is competitive or game-forcing.

A good solution in these sequences is to use 2NT as an artificial bid that
shows the weaker of the two hand types in the given situation. This allows
direct bids at the 3 level to be natural and the stronger of the two hand
types.

WHEN IS IT GOOD/BAD 2NT?

The biggest problem in using Good/Bad 2NT is knowing for sure whether it
applies to each possible situation. Expert practice varies widely.

The following 3 requirements must all be met, otherwise it is not Good-Bad
2NT:

Both sides have bid.

There have been 3 or more non-passes, and the most recent bid is 2 of a
suit by right hand opponent (RHO). Special case: if RHO made a weak jump
overcall, then 2NT is Good-Bad.

You wish to bid a specific suit that is lower in rank or (rarely) equal
to that of RHO’s suit.

The partner of the Good/Bad 2NT bidder usually bids 3C. Partner should make
some other bid to show suit preference, an unexpectedly long strong suit or
enough extra strength to force the bidding higher.

ALERT EXPLANATIONS

2NT is artificial and shows a hand that will compete in some suit at the
3 level that is of a rank lower than or equal to RHO’s 2 level bid.

If neither partner has invited or forced to game:

3 of a suit is natural and invitational (as opposed to competitive).

If either partner has invited but we are not yet forced to game:

3 of a suit is natural and game forcing (as opposed to competitive).

If the context of the auction shows which suit(s) the 2NT bidder is probably
competing in, that should be in the explanation.

Further information (if requested):

Responder makes the best bid for the situation, with a default to 3C.

COSTS AND BENEFITS

There is no free lunch in bridge. Good/Bad 2NT replaces 2NT as a natural bid
(or as a scramble or other conventional call). Fanatics will assure you that
no one wants to play a contract of 2NT, but some of the time you definitely
will regret the loss of this descriptive bid. Our experience is that Good/Bad
2NT is a clear winner in frequency and size of benefits.

Good/Bad 2NT requires some discussion, practice, and memorization. Initially
there tend to be many failures to alert and instances of giving misinformation.

A good approach is to play several sessions without using it. Try to identify
in the post mortems each situation in which it would have applied, both for
our side and the opponents.

Good/Bad 2NT provides an actively ethical solution to a class of bidding
problems that traditionally have been handled (unintentionally, of course) by
timing and body language. The convention occurs fairly often, typically once
to several times per session.

Furthermore, it is fun to use. It provides a basis for fine-tuning auctions,
usually without other changes in partnership agreements.

Good/Bad 2NT is a good tool for both sides, regardless of which side opened
the auction and what opening bid was made. It is equally useful at any
vulnerability and form of scoring. The Good/Bad 2NT convention is applicable
to virtually all bidding systems in which the 2NT bid has not already been
assigned some other special conventional meaning.

Miscellaneous notes

The 2NT bidder has the option to compete further after having limited the
hand. This might occur with extra length, especially in a minor, or after
partner has shown a preference that improves the hand.

In a close decision, it often is right to make the direct suit bid to show
the suit pattern of the hand. This goes well with a style of aggressively
inviting. It also anticipates a tendency of opponents to frequently bid
directly over the competing 2NT call, preventing the 2NT bidder from
clarifying the hand.

On the flip side, it can be right to compete with a very marginal hand and
hope that LHO will be enticed to take the immediate push.

Good/Bad 2NT can be used to distinguish between an average hand and a perfect
maximum within an already limited range. For instance, responder might use
it in this situation:

1D-pass-1NT-pass
2D-2S-?

We play that the Good/Bad 2NT bid is non-forcing (although rarely passed) but
some play it as forcing.

The basic rule regarding the number of non-passes might need to be modified
when a Forcing Pass system is in use by either side.

When is it not a Good/Bad 2NT situation?

Here are some cases where Good/Bad 2NT does not apply in our methods:

1. Only one side has made a non-pass.

2. There have been fewer than 3 non-passes in a competitive auction. In
these examples, we play 2NT as a natural game try:

1S - 2D- 2NT

1H - 1S - 2NT

3. RHO\'s bid is not a suit.

1S - 2H - dbl - ?

4. They use a convention at the two level against which we employ some
other predetermined defense.

5. The other side starts the auction with a strong artificial bid showing
at least 16 hcp.

Acknowledgements

Todd Walker (Milpitas, CA) developed most of the details of this approach.

The Good-Bad 2NT convention is explained (with a somewhat different set of
methods) by Marty Bergen in his book Better Bidding With Bergen Volume Two.

Marc Smith wrote an excellent series (again with different methods) in the
OKbridge Spectator.


标 题: Re: John Hoffman的Good-Bad 2NT


Good/Bad 2NT
From: John Hoffman (hoffman@hal.COM)
The Good-Bad 2NT convention is described by Marty Bergen (Better Bidding Vol
ume 2). Mike Lawrence has a similar convention with a different name in his
most recent book on Competitive Bidding.
As used in my partnerships, the convention is used by either partner in comp
etitive auctions to distinguish between
1. competitive and invitational hands (most frequent)
2. invitational and game-forcing hands (less frequent)
Going directly to the 3 level instead of using Good-Bad 2N shows invitationa
l values in case 1, and shows game-forcing values in case 2.
The Good-Bad 2N bid is artificial and shows a hand with the lower of the 2 p
ossible value ranges in each case. It is nominally forcing, and nominally re
lays to 3C (allowing the NT bidder to pass or select a signoff location). In
some cases, partner will correctly refuse to relay to 3C.
Our rules for when it applies differ somewhat from Bergen\'s. We play that it
is on under these conditions:
1. RHO\'s most recent call is a suit bid at the 2 level
2. our side has made at least one bid which is not a pass
3. the bid is obviously needed to distinguish the value ranges.
A few typical examples of Good-Bad 2N (opponent\'s bids in parentheses)...
1H - (Pass) - 1N - (2S) - ??
3H = invitational values, natural
3C or 3D = invitational values, natural
2N = Good-Bad 2N: competitive values, with suits unspecified
(1S) - DBL - (2S) - ??
3C or 3D or 3H = invitational values
2N = Good-Bad 2N
(1C) - DBL - (1S) - Pass; (2S) - ??
3C or 3D or 3H = invitational values (opposite a pass:
this should be a very strong single-suited hand)
2N = good-bad 2N (strong single-suited hand willing to compete)
1H - (1S) - 2D - (2S) - ??
3C or 3D or 3H = game-forcing
2N = Good-Bad 2N, only invitational opposite a minimum 2D bid


============================================================================
hbear收集到的资料:

标 题: Clarifying 2NT bids in competition


zz from:http://rsc.anu.edu.au/~mabraham/systems/Std_2NTinComp.doc

Clarifying 2NT bids in competition
Mark Abraham
(with acknowledgements to Marc Smith, Andrew Robson and Oliver Segal)
Theory: That when we have already shown a suit or suit(s) and the opponents
have entered the auction at the one- or two-level (other than by doubling, w
hich we largely ignore) then we will not want to use 2NT in a natural sense.

Instead 2NT is used to show a hand capable of three-level action in the cont
ext of the auction and vulnerability. Direct three-level action also shows a
hand capable of three-level action. However there are hands that are shapel
y and are merely contesting a part-score, and other hands which are interest
ed in playing in game that are in danger of being preempted out by the oppon
ents\' actions. We can utilize the 2NT-or-3-level choices to differentiate th
ese hand types.
2NT will sometimes be the stronger action, and sometimes the weaker action,
depending on the logic of the auction. The criterion that determines this is
the action(s) previously taken by the bidder\'s partner.
1. If partner has shown weakness, then there may be real danger that the opp
onents own this auction. Bidding 2NT with the weaker style of hand may allow
the opponents an easy \"action\" double leading to a penalty of our three-lev
el contract. Additionally we would like to act preemptively when we suspect
they own the hand. Hence, when partner has shown weakness, then direct three
-level action is weaker than going via the \"Good\" 2NT.
2. If partner has shown values, then we may be interested in bidding a game
constructively when the bidder holds the strong hand. We are also in grave d
anger of being preempted further, so that we need to take direct descriptive
action with our stronger hands. We do not mind further action by the oppone
nts (at the three-level) when we only had a hand contesting the part-score.
Hence, when partner has shown values, then direct three-level action is stro
nger than going via the \"Bad\" 2NT.
It remains to define what actions by partner show weakness, and which show v
alues. We choose that partner shows weakness only by passing, or by making a
n overcall at the one-level. All other actions show values. These choices se
em to work. A case might be made for adding Weak Jump Shifts by responder
(1C-P-2H with few HCP and 6+H) to the weakness definitions, but not Negative
Free Bids by responder.
The 2NT bids require partner to take correctable actions. When partner would
have passed a natural 3C bid that had the strength that has now been announ
ced by the 2NT bid, then partner must bid 3C, which the 2NT bidder will now
pass. If partner would have taken some action over a 3C bid, then he is obli
ged to either make the lowest bid he would have passed, or take some other s
trong action.
Doubles in such auctions are takeout unless otherwise defined (e.g. support
doubles).
An example is in order:
Here your negative double shows values, so partner\'s 2NT will be a weaker ha
nd.
Pard RHO You LHO
1H 1S X 2S
2NT Pass ?
¨ If you held Qxx xx Jxxx Kxxx then you would have passed if partner bid a
non-encouraging 3C, so you must bid 3C. If partner then bids 3D then you wil
l also pass, since partner\'s strength was expressed by 2NT. Likewise you wil
l pass his correction to 3H, which shows an opening hand with a likely seven
-card suit.
¨ If you held xx AQ xxxx KJTxx then you would again bid 3C, since partner\'s
2NT has already warned you that he is only interested in part-score. You wo
uld also pass any correction by him. (It is true partner might hold x KJxxxx
x AQJ xx but you will have another chance after his 3H bid; you certainly do
n\'t want to force the auction now, and be in 4H or 5C when he has xx Kxxxx K
x AQxx)
¨ If you held xx Kx AJxx KQJxx then you cannot bid 3C. Partner will pass ho
lding Jx AJxxx Qx Axxx when 5C is on, and will also pass holding Kxx AJxxx x
x Axxx when 3NT and 5C have play. You also cannot bid 3D, for partner will p
ass with x AJTxx KQxxx xx when 5D should be played. Likewise you cannot bid
3H, for partner will pass when holding Qxx AQJTxxx Q xx when game in hearts
will roll home. You should bid 3S to cater for all these possibilities. Clea
rly you are insisting on playing in game, and partner will cooperate by bidd
ing 3NT if he holds an appropriate stopper and hand.
¨ If you held AQx Qx KJxx KTxx then you are interested in playing a game op
posite any hand partner might have, and can bid 3NT to offer him that contra
ct (remember he has bid notrumps already, so your stopper needs to be full!)

There are a few sequences where the partner of the 2NT bidder has already ha
d the opportunity to show values, and has elected to pass. On these occasion
s, the level of contract is no longer in question, and a 2NT bid shows toler
ance for two contracts. 2NT will be this 2-way \"scramble\" bid only when it i
s clear that level of contract cannot be in doubt.
These notes are based on thoughts arising from the series in the OKbridge Sp
ectator in 1999 (available via http://www.okbridge.com for OKbridge members)
on 2NT bids in competition by British expert Marc Smith.
Other 2NT cases in competition
¨ When the opponents have opened a weak two or an anchored two-suiter, or s
omething similar, then we have Lebensohl continuations after a double.
¨ When the opponents interfere at the two-level over our 1NT bid (or equiva
lent) then we have Lebensohl continuations (and whatever doubles we have agr
eed).
¨ When we have opened a major suit and they have overcalled below 2NT or ma
de a takeout double then responder\'s 2NT shows be an invitational or better
hand with at least four-card trump support, and a cuebid shows the same valu
es with only three-card trump support. This allows opener to judge the degr
ee of fit, which is useful in finding the best game (3NT vs 4 of a major) an
d in judging the auction after further enemy competition. The alternate use
for the cuebid might be for hands that merely want a stopper to bid 3NT, but
these are rare, and can either bid their suit forcing or start with a takeo
ut double. The alternate use for 2NT would be natural, but these are again r
are, particularly if one excludes six-card minors, four-card majors, three-c
ard support and one requires more than a minimal stopper in a hand unsuited
for a trap pass.
· New suit non-jump bids are natural and forcing or not by agreement.
· Jumps in new suits are fit-showing, showing at least four-card trump supp
ort and the offensive values to play at the level we have forced our side to
play. These are better than jumps showing shortages in the case where we ca
n (and should!) anticipate further competition from the enemy.
· Jump cuebids of the enemy suit are splinters.
¨ When we have opened a minor suit, responder\'s 2NT can sensibly be played
as natural and balanced, with a cuebid showing an invitational or better rai
se to three of partner\'s minor suit.
The following sections provide clarifications in the various positions and s
ome sample auctions. These are provided only for completeness - except for h
ands with support for partner\'s suit, they can be derived from the above pri
nciples. An exclamation after a bid merely indicates a bid\'s alertable statu
s. A bid of 2Y or 3Y is a bid at that level in an unbid suit.
Sequences with 2NT bid by advancer
· Note that advancer is defined as the partner of the hand to make the firs
t defensive action in the auction (see, for example, Auctions 6, 7 & 8).
· A free bid by advancer will have values, and that the values are shown by
the choice of 2NT or 3-level action. (See footnotes 2 & 3 when raising part
ner\'s suit)
· When overcaller has shown near opening values or equivalent (2-level over
call, takeout double, strong 1NT overcall), then, when holding good values a
s advancer, we are concerned about being preempted. Thus 2NT shows a \"bad\" h
and and direct 3-level action is a good hand (Auctions 1, 2, 4 & 6). This mi
nimizes the effect of opener re-raising preemptively.
· From the alternate perspective, when overcaller does not or need not have
substantial values, then advancer will wish to act as high as possible with
weaker competitive hands to preempt the opponent\'s auctions (Auctions 3 & 5
).
· When the level of contract is not in question, usually because advancer\'s
range is known (and weak), then 2NT indicates two possible places to play,
and requests overcaller to act as his hand dictates. (See Auctions 7 & 8 in
the contexts of Auctions 1 & 2)
· The number of suits bid by the opponents is immaterial in deciding the go
od/bad status of 2NT, but will affect the type of hands that can be held for
the 2NT bids. (See Auction 2 vs Auction 4, and Auction 6)
Sequences Meaning
1 1S X 2S X2NT!3Y! ResponsiveBad (competitive to invitational)Good (GF)
2 1S 2H 2S X2NT!3H3Y! Responsive - minorsBad (competitive to invitational)4-
card raise Good (GF)
3 1H 1S 2H X2NT!3Y! Responsive - minorsGood (competitive to invitational)Bad

4 1S 2D 2H X2NT!3Y! Heart shortageBad (competitive to invitational)Good (GF)

5 1C / 1D 2S X XX2NT!3Y! BusinessGood (competitive to invitational)Bad
6 1S X 1D2D / 2S PX2NT!3Y! ResponsiveBad (competitive to invitational)Good (
GF)
7 1SP XX 2SP P2NT!3Y This pass limits the hand… (Auction 1)Two places to pl
ayClear preference for Y
8 1S2S / P P / 2DX 2H / 2SP P2NT!3Y! This pass limits the hand… (Auction 2)
Two places to playClear preference for Y
Sequences with 2NT bid by Opener
· The same principles apply here as for the sequences for advancer. When re
sponder has shown some values then we are concerned about further preemption
, and need to act at the 3-level with our good hands. When responder has not
shown strength, then we are concerned about being doubled at the three-leve
l, and so bid 2NT with our good hands.
· Auctions 1-5 are all identical in that responder has taken no action and
is probably a poor hand, hence opener needs to be concerned about being doub
led at the 3-level for penalties.
· In Auctions 6-11, responder has taken some action and opener is now usual
ly concerned with further preemption by the opponents, and thus bids good ha
nds at the three level to negate this.
Sequences Meaning
1 2S P P 1DX2NT!3Y! Spade shortageGood (normal 3-level rebid)Bad (shapely &
competing)
2 1S P 2S 1DX2NT!3Y! Spade shortageGood (normal 3-level rebid)Bad (shapely &
competing)
3 P / X P 2S 1DX2NT!3Y! Spade shortageGood (normal 3-level rebid)Bad (shapel
y & competing)
4 2H P P 1SX2NT!3Y! Heart shortageGood (3-level rebid, e.g. over 1NT respons
e)Bad (shapely & competing)
5 P / X P 2H 1SX2NT!3Y! Heart shortageGood (3-level rebid, e.g. over 1NT res
ponse)Bad (shapely & competing)
6 2H X P 1S2NT!3Y! Bad (bidding because I have to)Good (better than minimum,
or shapely, etc.)
7 2S X P 1D2NT!3Y! Bad (bidding because I have to)Good (better than minimum,
or shapely, etc.)
8 1H X 2H 1DX2NT!3Y! Heart shortageBad (better than minimum, or shapely, etc
.)Good (GF)
9 P / X 1H 2S 1CX2NT!3Y Spade shortage (or support double)Bad (just competin
g)Good (near GF)
10 P / X 1S 2H 1DX2NT!3Y! Heart shortage (or support double)Bad (just compet
ing)Good (near GF)
11 X XX 2H 1CX2NT!3Y! Heart shortageBad (just competing)Good (near GF)
Sequences with 2NT bid by Responder
The same principles apply here as for the sequences for advancer. When opene
r has shown some values then we are concerned about further preemption, and
need to act at the 3-level with our good hands. Opener is defined to be stro
ng once he has opened, so the good 2NT by responder doesn\'t arise.
Sequences Meaning
1 1D 2S X2NT!3Y! NegativeBad (just competing, could be weakish)Good (GF)
2 2S 1DX 1SP P2NT!3Y! Bad (forced to bid)Good (interested in things, not for

cing)
3 1S 1DX / 2D P2S PX2NT!3Y! Spade shortageBad (just competing, in context)Go
od (weird hand - x QT9xx x QJTxxx or xxx KQT9xx x xxx?)
Sequences with 2NT bid by overcaller
The same principles apply here as for the sequences for advancer. When advan
cer has shown some values then we are concerned about further preemption, an
d need to act at the 3-level with our good hands. When advancer has not show
n strength, then we are concerned about being doubled at the three-level, an
d so bid 2NT with our good hands. Typically such auctions only arise when we
have started with a double.
Sequences Meaning
1 2S X 1SP X2NT!3Y! BadGood (probably strong type for double)
2 2H P 1HP XX2NT!3Y! Takeout of HGoodBad (shapely, competing)
0

#3 User is offline   dvd 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 620
  • Joined: 2013-April-15

Posted 2013-August-28, 22:18

个人感觉使用这个约定叫的关键之处就是不能和自然意义的2n整混淆,否则后果可能是灾难性的!
所以,只推荐固定搭档在充分探讨过的基础上使用。
0

#4 User is offline   HeartA 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 2,016
  • Joined: 2004-October-17

Posted 2013-August-29, 13:02

太长。

简而言之,如果lebensohl用得熟练,那么好坏2NT也就问题不大。
Senshu
0

Share this topic:


Page 1 of 1
  • 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