Precision is a strong club system which uses 1♣ to open all strong hands (16+ HCPs), except hands that can be opened with a natural 2NT opening.
Openings
- 1♣: 16+, any shape;
- 1♦: 11-15, unable to open with any other bid;
- 1♥/1♠: 11-15, 5+ ♥s/♠s;
- 1NT: 13-15, balanced, no 5-card majors;
- 2♣: 11-15, 6 ♣s or 5 ♣s with a 4-card major;
- 2♦: 11-15 Mini-Roman, 3-suited hand short in ♦s;
- 2♥/2♠: weak two bids;
- 2NT: 22-24, balanced;
- 3♣/3♦/3♥/3♠: preemptive;
- 3NT: weak gambling 3NT.
Precision pass
A variant of the precision system is to open all hands above 8 HCPs, and invert the meaning of pass and 1♦[1]:
- /: 8-14 unbalanced or balanced hand outside the range of 1NT;
- 1♣: 16+ balanced or 15+ unbalanced;
- 1♦: 0-7, any shape (fert);
- 1♥/1♠: 8-14, 5+ ♥s/♠s;
- 1NT: 9-12 NV, balanced, no 4-4 majors; 13-15 V, balanced, no 5-card majors;
- 2♣: 8-11 with 4-4 majors or 19-20 balanced;
- 2♦: 5-9, two five-card suits but not both minors;
- 2♥/2♠: weak two bids;
- 2NT: 5-9, both minors (unusual 2NT);
Auction after the strong 1♣ opening
- 1♦: negative, 0-7 or any 4441;
- 1♥/1♠/2♣/2♦: 8+, 5+ of the suit, game forcing;
- 1NT: 8-10, balanced;
- 2♥/2♠/3♣/3♦/3♥/3♠: weak jump shift;
- 2NT: 11-13 or 16+ balanced;
- 3NT: 14-15, balanced.