Kaplan Inversion
This convention solves some problems for the sequence 1 - 1. It works like this:
1 - 1: 6 - 11 HCP, 0 - 4
1 - 1NT: 6+ HCP, 5+
Both bids are forcing, and can be combined with a 2/1 framework.
Opener's Rebid
1 - 1 - ?
1NT: 11 - 15, 4
2minor: 11 - 17, best minor (can be 3 cards if balanced)
2: 11 - 15, 6
2: 16+, Reverse
1 - 1NT - ?
2minor: 11 - 17, best minor (2 can be 2533)
2: 11 - 15, 6
2: 11 - 15, 3+