[mw64ahw]

We were playing Kaplan Inversion

---

South will bid 3♦

Spoiler

Trying to develop our bidding with a newish partner we were playing Kaplan Inversion as we had discussed earlier in the day, or so I thought, where 1♠ is either 6-10 or 5+♠ GI.
I dithered over 1♠ or 2♣ fearing a misfit/missing ♠s if I went 2♣

---

[LBengtsson]

Kaplan Inversion was part of some Precision system, I guess. Which one I do not remember. Here is a BBO forum link.

https://www.bridgeba...plan-inversion/

[mikeh]

Your description of Kaplan Inversion doesn’t match any description I’ve seen or (for a short period of time 30 years ago) used.

However, I think that it’s irrelevant to the problem both because your partner forgot and because the problem remains after a normal 1S response.

I’m not at all convinced that 4S is the correct bid for opener over 3D. He has great spades but he has only one Ace, his hearts are not solid (picture KQJxxx instead) and he has xx in diamonds. However, while 4S is a mild overbid, 3S is as much an underbid so I can live with 4S, especially since it could be played as denying a diamond control: 4D would be a big raise with a control although some would say 4S is simply a good raise but weaker than 4D which is a ‘super max’. Again, if that were the difference, I can live with 4S and actually think it’s the best call.

If 4S denies a diamond control then 4N is ok, although why anyone would play it as straight Blackwood escapes me. If 4S is silent on diamonds, then 4N is silly. Picture QJxx KQJxxx AQ x

Keycard doesn’t help. Responder can’t tell the difference between KQxx KJxxx AQx x and the actual hand.


Of course responder could use exclusion if available: 5D. Exclusion is usually a jump but it makes sense in this crowded auction….if partner is on the same page. Otherwise it’s dangerous

As it is, east doesn’t know about the spade King nor about the club control. It’s quite likely opener has shortness in clubs, given the bidding, or have Kx.

In any event, regardless of methods, responder is going to be guessing to some degree. So while 4N seems silly to me (not least because any serious partnership uses keycard or some other more sophisticated 4N once a suit has been established as trump) I think it largely irrelevant.

In short, freaks are difficult to bid without guesswork. Indeed, 6S seems like a logical bid directly over 4S. Maybe it fails but it has to have play opposite almost all hands consistent with the auction. Try as I might, I can’t see any way for responder to find out that partner has the hand he had…especially that club control. So grand, while definitely possible (from east’s perspective) would be a shot in the dark.

Btw, KI was invented by Kaplan while playing, I think, with Kay….after his partnership with Sheinwold ended.it was not in a big club system, but there’s no reason it can’t be played there as well. However, it’s never become popular with good players, and my limited experience persuaded me that there is no net benefit to it. The advent of methods such as BART has greatly improved the 1H 1N (forcing) approach and such methods, as far as I can see, don’t translate particularly well into KI, regardless of which variant of KI one plays.

[mw64ahw]

LBengtsson, on 2022-March-09, 08:31, said:

Kaplan Inversion was part of some Precision system, I guess. Which one I do not remember. Here is a BBO forum link.

https://www.bridgeba...plan-inversion/

I actually play as below, but this is perhaps of less interest than how others would bid on the hand itself
1♥-1NT 5+♠ 6-10
..2♣ Gazzilli type
..etc

1♥-1♠ forcing NT or 5+♠ GI
.. 1NT Balanced or 4+♦
....2♣ Which?
..2♣ 4+♣
..2♦ 4+♠ Min+ or 6+♥ Str or 25♥33 Str
...etc.

[mw64ahw]

mikeh, on 2022-March-09, 11:02, said:

Btw, KI was invented by Kaplan while playing, I think, with Kay….after his partnership with Sheinwold ended.it was not in a big club system, but there's no reason it can't be played there as well. However, it's never become popular with good players, and my limited experience persuaded me that there is no net benefit to it. The advent of methods such as BART has greatly improved the 1H 1N (forcing) approach and such methods, as far as I can see, don't translate particularly well into KI, regardless of which variant of KI one plays.

Or by Richard Granville with Granville being another name for KI5 with the main benefit being able to play in a 5-3/2 ♠ fit when 1♥ is opened

[mycroft]

Mike, at least part of the reason for KI's popularity in the ACBL is that it was taken off the GCC the same time they restricted NT overcall systems (Suction, CRaSh, et al). 1995 or so (to my very faulty memory)? We'll see if there's an uptick now that it's legal (as is said "too hard for players" defences to NT) on the Open Chart and the Open chart is "default".

I've never seen a requirement for it, either, but IIRC it is another answer to the Flannery problem. Which I've also not seen a requirement for :-)

[P_Marlowe]

Hi,

the jump to game by opener should show a (semi) bal. hand, at least if partner is NOT a passed hand,
if he is a passed hand, the game bid can be a gamble, i.e. the question i, what is / was wrong with
showing the shortage?

I am not even sold on bidding game with only a 44 fit, but this is a different discussion.

With kind regards
Marlowe