===== system after 10-13 NT =====
(based on //Roadmap// : http://www.geocities.com/daniel_neill_2000/sys/ )

  * 3!D = game INV or slam INV 55 majors (then 3!H/!S=refuses INV, 3NT=22 majors, 4!C/!D=accept in !H/!S)
  * 2NT = both minors (55 weak or 54/55 INV+) or weak with diamonds
  * 2!C = stayman, INV or weak. with weak hand, it will just bid 2!H over 2!D (both majors) or pass any other answer 
  * 2!D = GF stayman
  * 2!H / 2!S / 3!C / 3!H / 3!S = to play, NOT INV
  * 3NT = to play
  * 4!C/!D = transfer to !H/!S

after 1NT - 2NT, opener give preference, then responder may
  * pass
  * 3!D = to play with diamonds
  * 3!H/!S = notrump stopper, NOT singleton. possibly (31)(54). then opener bids 4m (passable), 3NT (passable, with stopper in the othe major), 4-other-minor=accept game, 4M=contract proposal with 5 card major.
  * 3NT = 55 minors, NO stopper in majors, passable
  * 4m in preferred minor = INV, passable
  * 4 other minor = slam try