When the right-hand opponent opens a weak 1 N/T (12 to 14 points) your bid of 2 Clubs asks your partner to bid his best major.

2C = both majors (at least 4-4)

Partner may pass with club length and a weak hand.

This bid would typically be used to show 13 to 15 points. A double would show 16 or more points.

Some partnerships use 2 Clubs for takeout with scattered strength and no good suit to lead.

They double to show a good attacking opening lead with enough high cards as entries to run the suit.

2C = both minors

2D = both majors