[gwnn]

I'd like to throw together two simple structure after a precisionish 1D opener.

1NT we like 10-12 or 14-16 in 1/2 or 3/4 seats. (16 hcp balanced hands will be opened 1C in 1/2 seats. 3/4 seats 1♣ promises 17)

so 1♦ is either an unbalanced hand with 4+ diamonds (or the rare (41)3♦5♣ with bad clubs) OR the other balanced range (13-15/10-13).

1♦-1♥/1♠ we just play standard stuff, it's OK. 1N should deny game interest opposite the 13-15 hand.

1♦-2♣/2♦. these are the sequences we don't know what to do with. To make things simpler these two deny 4cM's. Some artificiality seems in order.

[jtfanclub]

I happen to like 2♦ as natural and invitational.

2♣ is then artificial GF (or artificial 1rf by a passed hand if that's legal in your jurisdiction). Opener can then describe your hand by length or by shortness, your preference. You can even bid it with a 4 card major.

[rbforster]

It's not unreasonable to play basically what you play over a standard 1♦ opener, recalling that basically all the unbalanced hands have 4+ diamonds and the balanced ones will still have a relatively high average # (2-5, with 2 being quite rare). How about:

1♦-?

2♣ 5+ clubs GF
2♦ 4+ inverted, limit+ raise of diamonds with no 4cM (usually 5+ diamonds)
3♣ 6+ clubs invitational