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Group 1 results: Essex beat Durham by 44 runs, Warks beat Notts by three wickets, Worcs draw with Derbys
Group 2 results: Hants beat Middlesex by 249 runs, Glos beat Somerset by eight wickets, Surrey draw with Leics
Group 3 results: Yorks beat Kent by 200 runs, Lancs beat Northants by 206 runs, Sussex beat Glam by eight wickets
Glamorgan 285 & 349 v Sussex 481 & 38-1
Not too long to go now until tea.
Sussex batters Aaron Thomason (19 not out) and Stiaan van Zyl (11 not out) are holding firm with 116 runs needed to win and 39 overs to go.
Lancashire 305 & 296-7 dec v Northamptonshire 177 & 172-7
It appears as though Nathan Buck is deeming attack as the best form of defence for Northants, hitting three fours to move to 13 from 18 balls.
The runs are out of the equation for the visitors, needing 253 from 36 remaining overs, so this really is just about surviving the day.
Nottinghamshire 273 & 260 v Warwickshire 201-9 & 225-6
Warwickshire are just 108 runs away from the win now. Nottinghamshire need four wickets.
That would be some feat if the Bears can chase down 333 to win.
Stuart Broad is bowling. Tim Bresnan 23 and Olly Stone 14 are not out respectively. IT's all a little tense at Trent Bridge.
Glamorgan 285 & 349 v Sussex 481 & 29-1
A BBC Radio Sussex listener has joint pointed out that the 18 lbw dismissals in Glamorgan's game with Sussex have equalled a County Championship record.
Five other matches have seen 18 leg-before wickets. We could have a record-breaker at Sophia Gardens today.
Kent 265-9 & 163-6 v Yorkshire 379 & 330-5 dec
Image source, Getty ImagesEngland Test skipper Joe Root comes into the attack, replacing Dom Bess as Yorkshire search for a seventh wicket.
We've got 45 overs remaining in Canterbury.
Northamptonshire 152-7, Lancashire need three more wickets to win
Breakthrough!
It feels like it's been a long time coming but, with only his second delivery in the innings, Rob Jones has Tom Taylor stumped and Lancashire can breathe a sigh of relief.
They still have three more wickets to take but the door is ajar again at last.
Derbyshire 390 & 312-5 dec v Worcestershire 305 & 72-5
And a third wicket for Derbyshire's Ben Aitchison as he pins Gareth Roderick leg before for 22.
Derbyshire are five dismissals away now.
Glamorgan 285 & 349 v Sussex 481 & 15-1
Just the start Glamorgan needed as Tom Haines edges Michael Hogan to Andrew Balbirnie in the slips.
Sussex need another 139 runs to win.
Nottinghamshire 273 & 260 v Warwickshire 201-9 & 206-6
A double change for Nottinghamshire as Zak Chappell and Stuart Broad both return to the attack.
Warwickshire are 199-6 with Tim Bresnan seven not out and Olly Stone unbeaten on 10 not out.
The Bears need just 130 to win. This'll be a tense finish.
Surrey 672-8 dec v Leicestershire 375 & 144-3
A wicket has fallen at The Oval, meanwhile, meaning Leicestershire fans can't quite rest easy just yet despite Hassan Azad's fine 74 not out.
Colin Ackermann was the man to, caught behind off Amar Virdi for 29, bringing Lewis Hill to the crease.
Lancashire 305 & 206-7 dec v Northamptonshire 177 & 148-6
Full credit to Northants and Luke Procter here.
Under all sorts of pressure from Matt Parkinson and co, knowing one more wicket could well signal the beginning of the end, they continue to battle on just six down.
Procter has brought up his half-century and the fifty partnership with Tom Taylor, who's not out on 13.
Kent 265-9 & 152-6 v Yorkshire 379 & 330-5 dec
The other Ollie Robinson has just fallen for Kent, caught behind off the bowling of Duanne Olivier for 28.
In comes 44-year-old all-rounder Darren Stevens. He's rescued Kent so many times before, can he do it again?
He joins Matthew Milnes who has a career-best 60 not out.
Derbyshire 390 & 312-5 dec v Worcestershire 305 & 73-5
Elsewhere, Worcestershire are really starting to struggle now as Ben Aitchison has his second, trapping Riki Wessels for two.
The Pears still need a mammoth 326.
Glamorgan 285 & 349 v Sussex 481
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Glamorgan 285 & 349 v Sussex 481
And that'll mean Sussex will be clear favourites to wrap this one up.
It's also 13 wickets in the match for Robinson. He took 4-50 in the first innings too. Bravo!
Glamorgan 285 & 349 v Sussex 481
Wicket number nine for Ollie Robinson as Callum Taylor is caught by Stiaan van Zyl and falls for 84.
Remarkable stuff, 9-78 from 30.1 overs with 10 maidens.
Glamorgan 285 & 349-9 v Sussex 481
Henry Crocombe selfishly trapped Billy Root leg before yesterday for Sussex's only non-Ollie Robinson wicket of the innings.
Robinson, currently on 8-77, is unsurprisingly given another over.
Glamorgan 285 & 349-9 v Sussex 481
Incredible from Ollie Robinson who has his eighth wicket of the innings, and his third since lunch.
Timm van der Gugten has an 11-ball duck before being trapped lbw.
Michael Hogan is the new man in. Robinson could have a nine-for here.
Derbyshire 390 & 312-5 dec v Worcestershire 305 & 68-4
Ben Aitchison gets his first wicket of the match, as Brett D'Oliveira is caught by Fynn Hudson-Prentice for three.
Worcestershire are now four down and are in survival mode.
Nottinghamshire 273 & 260 v Warwickshire 201-9 & 185-6
Warwickshire's unlikely chase takes another blow as Dane Paterson has his third, bowling Michael Burgess for one.
Olly Stone joins Tim Bresnan (three not out) in the middle.
Image source, Rex Features