About Modern Minors
In Modern American bidding, we define the minor suit openings to be more restricted than Standard American or 2/1 bidding systems.
Opening 1♣ shows 1 of 2 types of hands: - A balanced hand with 12-14 HCP (and no 5-card major). It may have as few as 2 clubs and could have longer diamonds. This includes hands with 2 clubs and 5 diamonds, assuming no shortness in the major suit. - Or an opening hand (11-21 HCP) with a long club suit. A long suit is considered a 'rebiddable suit' as the opener will most likely need to rebid clubs after partner's response
Opening 1♦ shows an unbalanced hand and at least 4 diamonds. If the hand has no singleton or void, it must have 6 or more diamonds (6-3-2-2) or (7-2-2-2) shape. A 1♦ opening hand will have at least 11 HCP and up to 21 HCP.