Commentary of every game available at top of this page
All 18 counties split into three regional groups of six
Each side will play five games
Two sides with most points play five-day final
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Northants v Somerset 110-8
Wickets are still tumbling at Northants and Ben Sanderson has five!
Jamie Overton is the eighth Somerset man to fall as he gets a leading edge to skew one to mid-off.
Sanderson has the superb figures of 5-26.
Image source, Getty ImagesGloucestershire 102-3 v Warks
And now Ben Charlesworth is the latest half-century maker to fall.
Warwickshire skipper Will Rhodes brings himself into the attack and immediately gets his man five balls later.
A measured knock that from Charlseworth, his 51 coming from 124 balls.
Dearden lbw b Conners 70 (Leicestershire 115-5 v Derbs)
Not long after getting the first half-century of the day, Harry Dearden is trapped lbw by Sam Conners for 70.
The 23-year-old was closing in on his highest first-class score of 87.
Big breakthrough for Derbyshire.
Northants v Somerset 96-7
Meanwhile at Northants, Somerset have just lost their seventh wicket.
Craig Overton falls to Ben Sanderson giving the Northants quick his fourth wicket.
Cook c Clarke b Virdi 42 (Essex 98-4 v Surrey)
Alastair Cook is gone!
The Essex opener tries to drive Surrey spinner Amar Virdi but snicks it to slip where Rikki Clarke grabs on superbly with one hand.
Image source, Rex Features
Gloucestershire 98-2 v Warks
Gloucestershire opener Ben Charlesworth has paced this innings beautifully.
His 50 comes up after 111 balls.
The ball is doing less and less with every delivery at Bristol. Charlesworth will want to stick around with these batting-friendly conditions.
Durham 71-3 v Lancs
Durham are digging in against Lancashire with opener Alex Lees still at the crease on 38.
Lees made 106 against Yorkshire in the second innings of the last round.
He's joined by Gareth Harte who's scored just seven from 45 balls at a strike rate of 15.56.
Middlesex 85-4 v Hants
Max Holden's two and a half hour vigil for Middlesex has just come to an end - the youngster goes to Keith Barker for 36.
Middlesex are four down and struggling.
Yorkshire 104-4 v Notts
Yorkshire are starting to rebuild after losing four early wickets in the first 20 overs.
Harry Brook and Jonathan Tattersall have just taken the visitors past 100.
Their partnership has also gone past 60 runs.
Worcs 101-3 v Glamorgan
Pears opener Jake Libby also reaches his fifty at New Road.
It comes of 94 balls including seven fours and Worcestershire are going along alright.
Leicestershire 90-4 v Derbs
Every batsman has struggled at Grace Road today.
Well all except Leicestershire's Harry Dearden. The 23-year-old has just brought up his half-century from 84 deliveries.
That's the first half-century on a day dominated by the bowlers so far.
Image source, Rex FeaturesHildreth c Rossington b Sanderson 32 (Northants v Somerset 77-6)
Big breakthrough straight after the interval!
Northants paceman Ben Sanderson gets one to lift and James Hildreth can only fend it behind.
Somerset now in huge trouble as Roelof van der Merwe joins Craig Overton.
Essex 69-3 v Surrey
Alastair Cook resumes on 34 for the hosts at Chelmsford.
It was Surrey's morning, can the former England batsman wrestle the initiative back to the reigning county champions?
Welcome back.
The players are beginning to make their way back out after lunch.
An intriguing afternoon session awaits...
Image source, Getty ImagesEssex 65-3 v Surrey - lunch, day one
Nick Gledhill
BBC Essex
A fascinating morning here at Chelmsford which saw Surrey fight back after Essex looked comfortable having chosen to bat.
Essex were 49 for the loss of Nick Browne who had given Gus Atkinson a debut wicket with a loose drive to mid off.
Then James Taylor, in his fourth first-class game, exploited movement in the air to claim Tom Westley and Varun Chopra with consecutive deliveries.
He very nearly got Sir Alastair Cook with an excellent hat-trick ball but Cook otherwise looked secure in reaching 34 at lunch.
With no Ryan ten Doeschate Essex could do with Cook batting long into the afternoon.
Durham 59-3 v Lancs - lunch, day one
Martin Emmerson
BBC Newcastle
Durham chose to bat in brilliant sunshine, but just like last week when it was damp, they were quickly in trouble.
Sean Dickson was the first to depart as he edged a Tom Bailey ball behind. Initially it looked like the keeper Alex Davies had gone the wrong way. But he seemed to adjust in mid air and took an excellent one-handed catch to remove the batsman for two.
Cameron Steel then departed for one as he left a ball from Luke Wood which thudded into his pads. It's Wood's first wicket for his new county.
And I am not sure what David Bedingham was doing when he got himself out for five. He casually wafted at a ball from Richard Gleeson which was outside of off stump and should have been left well alone. It didn't look good and he was caught behind.
At least Alex Lees has offered some resistance with 32 runs from 96 balls. He just needs someone else to be able to do the same.
With the players at lunch, myself and Josef will take a short break.
Back in a bit.
Bob Willis Trophy - day one
North group:
Durham 59-3 v Lancashire
Leics 84-4 v Derbys
Notts v Yorks 67-4
Central group:
Gloucs 83-2 v Warwickshire
Northants v Somerset 74-5
Worcs 77-3 v Glamorgan
South group:
Essex 65-3 v Surrey
Kent v Sussex 91-3
Middlesex 76-3 v Hants
Alrighty, let's have a look at those lunchtime scores then...
Davies b Sanderson 13 (Northants v Somerset 74-5)
Right on the stroke of lunch Somerset batsman Steven Davies is bowled by Northants quick Ben Sanderson.
And that will indeed be lunch with Somerset in all sorts of strife.
James Hildreth is the only chink of light... he's still there on 31.