You can't assume anything until you define the possible responses to the -X, i.e. 2♦ no 4 card major minimum so 5+♦ (3352,2353) 2♥ minimum w/3+♥ (2344,3343,3334 worst cases) 2♠ minimum w/3+[sp}] (3244 worst case) 2NT 18-19 balanced 3♣ forcing 1 rd initially both 4 card majors 3♦ invitational w/6♦ 3♥ invitational w/4+♥ 3♠ invitational w/4+♠&<4♥ 3NT long running ♦suit 4♣ splinter for either major 4♦ 6+♦ with one 4 card major 4♥ to play 4♠ to play one possible version of responses