Nebulous 2♣

After 1M opening all bids on level 2 are almost GF and show 5+ card suit. 

The exception is 2♣ bid, which shows:

3 card support 10-12, invitational

3 card support 13+, can hold 5 card side suit if balanced

5+ card ♣ suit, invitational

5+ card ♣ suit, GF

any balanced hand, can hold 4 card oM, GF

4441M, GF

After 1♥ - 2♣    ➲

After 1♠ - 2♣    ➲

If opps double 2♣ bid, OP's pass shows values in ♣, RE must redouble. Other bids are system on.

if opps overcall 2♣ bid, OP's pass shows values in the suit bid, double denies them.