A strong minor system is a bidding system where a 1♣ or 1♦ opening is strong, forcing and artificial. As the strong opening is made a level lower than the standard strong two clubs opening, it is made with less strength (usually 16+ HCPs). Therefore, all other opening bids (sometimes with the exception of natural 2NT and 3NT) are limited to a maximum of 15 HCPs.
Strong club systems are classified as blue sticker by WBF, if the other openings and responses are mostly natural.
- Constructive auctions are more accurate as the strong bid is made at a lower level.
- As the 1♣ or 1♦ opening is taken up, more minimum hands need to be opened with the other 1-level openings, especially the other minor. Generally, it is not advisable to combine 5-card majors with strong club/diamond opening as the burden on the other minor is large.
- It is vulnerable to aggressive overcalls, both at the 1-level and the 2-level.