Seems like many are not satisfied with bidding after precision 1♣opening, so here is what i play : 1♣- 1♦= 0-7 hcp 1♥= 8-11 hcp, balanced or 5+major 1♠= 12+hcp, any 5+card unbalanced (not 5332) 1NT= 12+hcp, balanced 2♣= 8-11 hcp, 6+♣ or 5+♣ with 4major 2♦= 8-11 hcp, 6+♦ or 5+♦ with 4major 2♥= 8-11 hcp, both minor: 4-5/5-4 or better 2♠= 12+hcp, both minor: 4-5/5-4 or better 2NT= 12+hcp, all 4441 3X= 8-11 hcp, 4441: singleton in bid suit After first answer opener can bid natural or relay. If interest i can write more later. Have a nice day