It sometimes amazes me how thinking through one issue in one context often translates into an unexpected idea for a different sequence, completely unrelated. I have found through the years that experience with various systems and conventions has expanded my thinking in this way, and I was recently reminded of this when considering a specific circumstance.
In my book, New Frontiers for Strong Forcing Openings, I realized that limitation of strong balanced hand pattern by splitting these between hands with known spades and hands without known spades did wonders for minor-suit sequences.
Then, I though last night about a much more mundane sequence. LHO opens a weak two in a major, and partner overcalls 2NT, passed to you.
As a quick but related aside, this reminded me of a funny sequence. Playing with an insane partner years ago (more insane than me), a 2S opening was passed around to me. I balanced as an unpassed hand with a 2NT call with a questionable holding. I had 1534 pattern with the stiff spade King, nice primed values.
Partner advanced with 3S. What the heck was 3S? We had forgotten to discuss this sequence! RHO doubled, and it was up to me.
This seemed great! I bid 4H. This could never go wrong. If partner took this as natural, I have five hearts. If partner took this as a "flag" showing great clubs, I had great clubs. If partner took this as RKCB for clubs, same happiness. If partner took this as a cuebid, I was looking at the heart Ace.
4H was passed out. Partner had a void in hearts and took me for balancing with a solid heart suit and the spade King. Huh?
The funny thing was that the other top-flight team that we played for those 7 boards ended up in a 4-1 heart game two hands later. When Declarer flipped out on Dummy, I commented that at least he got a stiff!
Anyway, back to the bidding. It dawned on me that a good tweak to advancing 2NT overcalls makes sense, along the lines of "New Frontiers" when a major is already out of focus:
3C = Puppet Stayman. Partner bids three of the other major with 4, three of the major with 5. If partner bids 3D, 3H and 3S become flags (3H showing clubs, 3S showing diamonds) with either slam interest or game strain uncertainty (meaning, no stopper bolster).
Transfer to other major = normal.
Transfer to THEIR major = clubs (and either slammish or strain uncertainty, or even bust)
3S = diamonds (and slam or strain or bust)
This seems so obvious now...