2/1 systems are as varied as Chevies. Make sure you and your partner agree on which style you're playing.

2-over-1-Systems.md

Question	Lawrence	Hardy	Robinson	Pavlicek	F. Stewart
1♥-2♦;2♥ shows 6/strong 5	No	Yes	No	Yes	Yes
1♥-2♦;2NT shows stoppers	Yes	No	Yes	No	No
1♥-2♣;3♣ shows extras	Yes	No	Yes	No	No
1♥-2♣;2♠ shows extras	Yes	No	Yes	No	No
1♥-2♦;3♣ shows extras	Yes	No	Yes	No	Yes
1♥-1NT denies opening strength	Yes	No	Yes	No	Yes
1♦-2♣ is 100% game forcing	Yes	Yes	No	No	No
1♠-2♣;2X-3♣ is game forcing	Yes	Yes	Yes	No	No
1♠-2♣;2X-(not 3♣) is game forcing	Yes	Yes	Yes	Yes	No