[barmar]

pescetom, on 2019-August-22, 10:10, said:

That might qualify for a Pre-alert, see the paragraph 'Systems that may be Fundamentally Unfamiliar to the Opponents'. It's not a common method like normal un-swapped strong NT.

Not sure this one change makes it a whole new "system". I think that criteria typically means something like canape bidding or extremely light openings.

Then again, players generally pre-alert Kaplan Interchange, which is a comparable tweak. Is that required, or just something they do voluntarily?

[pescetom]

barmar, on 2019-August-23, 08:54, said:

Not sure this one change makes it a whole new "system". I think that criteria typically means something like canape bidding or extremely light openings.

Then again, players generally pre-alert Kaplan Interchange, which is a comparable tweak.

One might argue that inverting the natural meanings of 2NT and 1x 2NT is as radical as canape and more unfamiliar too, or at least around here. About 20% of my opponents play canape but I've never (knowingly) met this inversion. What are the presumed advantages, other than increasing the percentage of hands that get played with some level of Systems On?

[barmar]

pescetom, on 2019-August-23, 09:10, said:

One might argue that inverting the natural meanings of 2NT and 1x 2NT is as radical as canape and more unfamiliar too, or at least around here. About 20% of my opponents play canape but I've never (knowingly) met this inversion. What are the presumed advantages, other than increasing the percentage of hands that get played with some level of Systems On?

I never said it had advantages, I don't even know if anyone actually plays it. It was just something that the post about 2NT=21-21 brought to mind.

The usual reason for pre-alerts is that it allows the opponents a chance to agree on a defense to something unusual, which they might not have discussed before. What kind of defensive change would be needed for this swap?

Here's a possible advantage. 2NT-AllPass frequently goes down -- declarer is constantly end-played, and doesn't have entries to dummy to take finesses (this result frequently prompts someone to point out that it should always be doubled, and then someone else says they'll start passing with values as a counter). If you lower the strength for opening 2NT, this is less of a risk. And if you rebid 2NT with the stronger hand, you have the protection of knowing partner has some values (it's effectively a game force, unless partner responded very aggressively).

[jeffford76]

barmar, on 2019-August-23, 08:54, said:

Then again, players generally pre-alert Kaplan Interchange, which is a comparable tweak. Is that required, or just something they do voluntarily?

In the ACBL the alerting rules for the old charts said to pre-alert everything that was not on the general chart. Kaplan Inversion wasn't on the general chart. (Well it wasn't, and then it was, and then it wasn't again.)

[blackshoe]

Given how people complain about rules changing "so often" it's not all that surprising that they don't (can't?) keep up with what the rules are today. :-)

[barmar]

As I mentioned in a BW thread a day or two ago, the rules don't change as often as people think they do.

[blackshoe]

I know that, Barry. Unfortunately, a lot of players who should also know that seem to either not know it or to conveniently forget it when they want to rant about something.

[barmar]

blackshoe, on 2019-August-29, 15:17, said:

I know that, Barry. Unfortunately, a lot of players who should also know that seem to either not know it or to conveniently forget it when they want to rant about something.

People will always find an excuse to rant.

[blackshoe]