Somerset's pursuit of a first County Championship title will resume with a home fixture against Nottinghamshire when the second phase of the revamped competition gets under way.
Six teams will be in contention for the trophy from 30 August in Division One.
Counties will play a further four matches against teams they have not already met in the group phase, with the top side winning the Championship.
Top-tier leaders Warwickshire face Lancashire at Emirates Old Trafford.
Hampshire host Yorkshire in the other fixture, and the top two teams in Division One will then also contest the five-day Bob Willis Trophy final at Lord's, starting on 27 September.
The remaining 12 teams that do not go into Division One move into Divisions Two and Three, in which teams will play another four matches.
Opening Division One fixtures
Monday, 30 August:
- Hampshire v Yorkshire (Ageas Bowl)
- Lancashire v Warwickshire (Emirates Old Trafford)
- Somerset v Nottinghamshire (The Cooper Associates County Ground)
Each county played 10 four-day games in the first group stage - five home and five away - with the final round in mid-July.
The competition took a scheduled break for The Hundred and One-Day Cup with the top two teams in each group progressing to Division One and carrying over the points from the matches played against each other.
As it stands
1. Warwickshire (21 points)
2. Somerset (18.5)
3. Lancashire (16.5)
4. Hampshire (8.5)
5. Nottinghamshire (5)
6. Yorkshire (4.5)
1. Essex (19 points)
2. Northamptonshire (16)
3. Surrey (13)
4. Gloucestershire (12)
5. Glamorgan (11.5)
6. Durham (4)
1. Worcestershire (18.5 points)
2. Middlesex (13)
3. Sussex (12)
4. Leicestershire (11.5)
5. Kent (11)
6. Derbyshire (9.5)