[Chamaco]

Hi all,
suppose you are playing 2/1 GF with Kaplan Inversion.

BACKGROUND ASSUMPTIONS

There are a bunch of ways to play KI, so let's assume that the uncontested auction framework would be:

1H- ?
....- 1S= 1R force, unlimited(can be GF only if holding 4spades), denies 5+ spades, may have 4. Opener responds
.............- 1NT if holding 4 spades
.............- other bids as if responder had bid 1NT forcing, e.g. suit rebid = 6+ bagger, or rebid a 3 card minor suit
....- 1NT= 1R force, unlimited, shows 5+ spades. Natural followups by opener

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

THE QUESTION

I like very much KI in uncontested auctions, but I'd love to know from other KI "aficionados" how they handle sandwhich overcall, especially preemptive.

I listed below almost all the sequences. The first set refers to interference after the 1S response, the 2nd set to when it occurs after the 1NT response.



FIRST SET: OVER 1S response

SEQUENCE 1- double showing spades

1H-(p)-1S-(DBL)


SEQUENCE 2- double showing strength

1H-(p)-1S-(DBL)


SEQUENCE 3- simple overcall

1H-(p)-1S-(2m)


SEQUENCE 4- preemptive overcall

1H-(p)-1S-(3/4m)


SEQUENCE 5- 2S showing spades

1H-(p)-1S-(2S)


SEQUENCE 6- 2H/2NT showing a 2-suiter

1H-(p)-1S-(2H/2NT)

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


SECOND SET: OVER 1NT response

SEQUENCE 7- double

1H-(p)-1NT -(DBL)


SEQUENCE 8- simple overcall

1H-(p)-1NT -(2m)


SEQUENCE 9- preemptive overcall

1H-(p)-1NT -(3/4m)


SEQUENCE 10- 2H/2NT showing a 2-suiter

1H-(p)-1NT -(2H/2NT)

[Gerben42]

FIRST SET: OVER 1S response

SEQUENCE 1- double showing spades

1H-(p)-1S-(DBL)

Redouble showing strength, 1NT stopper in Spades, Pass "nothing to bid", usually 5332.

SEQUENCE 2- double showing strength

1H-(p)-1S-(DBL)

Same except 1NT shows 4-card Spades, not a stopper.

SEQUENCE 7- double

1H-(p)-1NT -(DBL)

Rdbl for strength, Pass for weakness.

All the others are the same as had there been no Kaplan Inversion.

[Chamaco]

Gerben42, on Jun 20 2005, 08:57 AM, said:

FIRST SET: OVER 1S response

SEQUENCE 1- double showing spades

1H-(p)-1S-(DBL)

Redouble showing strength, 1NT stopper in Spades, Pass "nothing to bid", usually 5332.

SEQUENCE 2- double showing strength

1H-(p)-1S-(DBL)

Same except 1NT shows 4-card Spades, not a stopper.

SEQUENCE 7- double

1H-(p)-1NT -(DBL)

Rdbl for strength, Pass for weakness.

All the others are the same as had there been no Kaplan Inversion.

SEQUENCE 4- preemptive overcall

1H-(p)-1S-(3m)
=================

How does opener show 4 spades and a minimum opener ?
Responder might have still 4 spades and we might lose a 44 fit.

What does DBL mean and what are its hcp requirements ?

And what would the following sequence mean ?

1H-(p)-1S-(3m)
p-(p)- DBL

[Gerben42]

Quote

1H-(p)-1S-(3m)
=================

How does opener show 4 spades and a minimum opener ?
Responder might have still 4 spades and we might lose a 44 fit.

This will be tough but 3m made it hard. With a minimum opener you pass 3m, simple as that. Responder's balancing double is negative and at least 10+ HCP or similar.

[Chamaco]

Gerben42, on Jun 20 2005, 09:15 AM, said:

Quote

1H-(p)-1S-(3m)
=================

How does opener show 4 spades and a minimum opener ?
Responder might have still 4 spades and we might lose a 44 fit.

This will be tough but 3m made it hard. With a minimum opener you pass 3m, simple as that. Responder's balancing double is negative and at least 10+ HCP or similar.

Question 1.
What about opener's X meaning ?

a. general extra strength ?
b. takeout ?

Question 2 (related to Q1)
Can opener's pass be a trap pass (I suppose this depends on whether DBL is T/o)?