Kaplan Inversion being X

[lyncserver]

Dear all,

 

Playing Kaplan Inversion / Interchange, it seems that opponents have a free double and it is not easy to deal with.

Is there any suggested defence after 1H - 1S(KI) - (X)?

 

Thanks,

Lync

[glen]

Pass = no extra values, exactly 5♥s, no five card minor. XX by responder asks further description, can be passed with four good ♠s. 1NT by responder is like 1♥-1NT forcing asks further description, 2m is to play.

XX = extra values, no five card minor, not a 1NT rebid. Cannot be passed. 1NT by responder like 1♥-1NT forcing, asks further description.

1NT = extra values but still a 1NT rebid, ♠ stopper(s).

2m: five card or longer minor, can have extra values.

2♥: 6 or longer ♥s, minimum.

2♠: short in ♠s, extra values, 4-3/3-4/4-4 in minors. 2NT asks best minor.

3m: five card or longer minor, forcing to 3NT or 4m.

2NT and other jumps: whatever a jump shows in your system, but not a defensive hand that will XX first.

[fromageGB]

Well, it is easy to deal with, as you can just ignore it and bid as you normally would.

 

However, you have the opportunity to describe your hand better by agreeing meanings, much along the lines of glen's suggestion. I vary that by having 2bids showing length (5 if new) and not strong (typically up to 14hcp) with stronger hands bidding 1NT or XX (which can include a 5 card minor, forcing when bid later). (Gazzilli is off, 2♣ is weak and 5.)

 

Crucial you have an agreement on 2♣ if you normally play it as artificial.

[PhilKing]

Redouble = decent 4-card spade suit, any range

Pass = 3 decent spades balanced or 4 weak spades

Others = nat

 

Let's punish them!

[lalldonn]

I have played KI a lot with opener's rebids as transfers (1NT = clubs or balanced). I would play redouble as four spades, pass as nothing to say (usually balanced, four bad spades possible), and keep transfers on except now 1NT promises clubs. And though I haven't done this, I would want to use 2♦ and 2♥ both as hearts to split up the ranges somehow since they will often compete in spades next.

[PhilKing]

I have played KI a lot with opener's rebids as transfers (1NT = clubs or balanced).

 

Looks like we play it "almost" the same.

 

I like playing 1NT differently - balanced or diamonds or a good 2♥ rebid - sort of a two under transfer. The advantage is that you can now play 2♣ as a relay (9+), 2♦ 5-8 to play opposite 3 2♥ 5-8 etc.

[lalldonn]

I have heard of that and it's not bad. I prefered to keep 1NT as fewer options so it could more easily be passed, which was generally a good result when it occured. But this was in a strong club system where you could pass opener's rebid much more freely than in standard.

[JLOGIC]

I have played KI a lot with opener's rebids as transfers (1NT = clubs or balanced). I would play redouble as four spades, pass as nothing to say (usually balanced, four bad spades possible), and keep transfers on except now 1NT promises clubs. And though I haven't done this, I would want to use 2♦ and 2♥ both as hearts to split up the ranges somehow since they will often compete in spades next.

 

This is what kevin and I play except pass is always 5332. Almost everyone plays X as t/o of hearts, maybe it's better to play something else over X showing spades but I don't.

[fromageGB]

All this seems very strange, to me. I play KI, and the way I play 1♠ denies 5+ spades, and can be zero spades. Equally opener has denied spade length by opening 1♥. 1♥ p 1♠! X therefore, while it is still technically a takeout double of hearts, definitely shows spades.

 

Consequently "punishing them" with XX when you have a 12 count and 4 spades is more likely to give them a top. If you want to keep things natural, and keep a possible 4-4 spade fit in the frame, you could say that XX shows 4 reasonable spades, but usually forcing, not penalty, when responder does not have 4.

 

Personally, I would not want to waste the natural 1NT bid as a possible contract, particularly as my preference is not to open 1NT with a 5 card major.

[PhilKing]

All this seems very strange, to me. I play KI, and the way I play 1♠ denies 5+ spades, and can be zero spades. Equally opener has denied spade length by opening 1♥. 1♥ p 1♠! X therefore, while it is still technically a takeout double of hearts, definitely shows spades.

 

Consequently "punishing them" with XX when you have a 12 count and 4 spades is more likely to give them a top. If you want to keep things natural, and keep a possible 4-4 spade fit in the frame, you could say that XX shows 4 reasonable spades, but usually forcing, not penalty, when responder does not have 4.

 

Personally, I would not want to waste the natural 1NT bid as a possible contract, particularly as my preference is not to open 1NT with a 5 card major.

 

 

The redouble shows 4 decent spades.

 

The point is to handcuff the fourth player - he will often run even when partner was going to, and he will often be running into trouble. If he passes, responder only passes with 3+ spades and a reasonable response - if that is handing them a top, they will have to work hard for their money. We have lost exactly nothing playing this defence to a double, since it in no way commits us to spades.

 

The point about this auction is that RHO is stepping into a misfit auction - if he has a typical take-out double shape with 42 in the majors, lefty will have 4 or five hearts and a weak hand with no clear bid a large proportion of the time. If we play that pass shows a balanced hand with potentially two spades he can pass with any hand (typically a 2533 4 count on which they were about to be incinerated), since partner will never have a hand that can pass out One Spade doubled. If we have the balance of the points, there is a good chance that we should defend a doubled contract. If we don't, it's a misfit for us as well, so we are best off pressuring him into premature action.

 

I generated a few hands and this one shows the standard situation:

 

..........9 7 2

..........6 3

..........9 5 4

..........A K Q J 4

10 8.......................K Q 6 4

10 9 7 4...................K 2

A 10 2.....................K Q 8 7

10 7 3 2...................9 8 6

..........A J 5 3

..........A Q J 8 5

..........J 6 3

..........5

 

If the auction starts 1[h]-p-1-x and you play pass as balanced, West can pass and North will bid, but you have them nailed for a monkey after a redouble.