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Eight games start on Sunday - four each in Divisions One and Two
Division One leaders Surrey playing Kent at Canterbury
Durham, who are top of Division Two, hosting Glamorgan
Kent 284-8 v Surrey
Dom Sibley produces some T20 fielding by catching a Jordan Cox slog off Will Jacks towards cow corner as he leaps over the rope. He flicks it back into the field before landing and as Cox remained on one knee throughout, fearing he would be out but hoping for a six, in the end Sibley has saved six runs.
Two overs until the new ball and Cox looks keen to make the most of them. He has 129.
Essex 292-3 v Somerset
80 overs have been bowled by Somerset and, with two Essex batters extremely well set, they waste no time in grabbing the new cherry.
That decision almost pays off straight away as Alastair Cook inside-edges narrowly wide of his leg stump off the bowling of Matt Henry.
Kent 277-8 v Surrey
Jordan Cox has moved on to 123. This is his best return since hitting 158 against Gloucestershire on 14 June last year. He must have realised he's too good to go a full year without a century.
Wes Agar has showed an array of shots to move to 39 off 53 deliveries, particularly enjoying the spin of Dan Moriarty whom he hit for nine in his previous over.
The partnership is 78 from 16 overs.
Notts v Warwickshire 259-3
Dan Mousley joins Alex Davies and fellow not out batter Sam Hain in reaching a half-century for Warwickshire.
It's been a busy knock by the left-hander.
Essex 289-3 v Somerset
Shoaib Bashir hasn't taken a wicket yet but he hasn't looked out of place on his first-class debut for Somerset.
The teenage off-spinner has figures of 0-73 from his 25 overs, but he hasn't been afraid to give the ball a bit of air and hasn't looked overawed by the occasion either.
Lancashire 50-0 v Hampshire 142
Phil Salt and George Balderson have ridden their luck somewhat but they have reached the first milestone at the end of the 10th over.
40 of those runs came by way of boundaries with four twos and two singles. Efficient stuff from Lancashire.
Salt has 34 at better than a run-a-ball. Old habits, eh!?
Essex 283-3 v Somerset
First-class century number 74 for Alastair Cook, but surprisingly it's his first in the County Championship in 2023.
The former England captain clips a ball off his legs for four to bring up three figures.
There's a wave of the bat to the crowd and a hug from Matt Critchley.
Kent 253-8 v Surrey
Wes Agar thumps Gus Atkinson through the covers for four to move to 29 from 44 balls.
That's just the fourth batting bonus point they have collected in their seven matches.
The Cox and Agar partnership has also passed 50. Useful runs.
Derbyshire spinner Mark Watt has just picked up the big wicket of Yorkshire captain Shan Masood for 67. But Yorkshire are still well ahead in the game after skittling their opponents for 111 before lunch. They're 200-3 and lead by 89.
Sussex all-rounder Nathan McAndrew is leading a counter-attack against Worcestershire. The Australian has 63 off just 62 balls with his side now on 249-7.
Glamorgan continue to pile on the runs against Division Two leaders Durham. Kiran Carlson's unbeaten ton has taken them to 274-4.
And they're going to attempt a restart at 17:30 BST at Bristol with Gloucestershire on 45-0 against Leicestershire.
Image source, Getty ImagesNotts v Warwickshire 244-3
It's been steady stuff from Sam Hain but he and his Warwickshire colleagues are batting the Bears into a very strong position at Trent Bridge.
Essex 277-3 v Somerset
Alastair Cook straight-drives Josh Davey down the ground for four.
Onto 99 now...
Kent 239-8 v Surrey
Jordan Cox scored 159 run runs in his first 10 innings of the season. His highest score was 30.
The 22-year-old has just completed a sensational century, the fourth of his burgeoning career, with a reverse sweep of Dan Moriarty. That was his 14th four to go with a six. 166 balls to get there.
Wes Agar has provided able support and given Kent a real chance of a batting bonus point, something which seemed unthinkable at 41-5.
That's the first Division One century of this round of the County Championship and, with the nerves out of the way, he clubs Moriarty over deep mid-wicket for another six.
Essex 270-3 v Somerset
I was joking earlier on when I said Matt Critchley might get to a century before Alastair Cook but, you know what, he might end up doing it!
When Cook scored his 94th run, Critchley was 22 not out. Cook remains on 94, but Critchley is now on 68.
Image source, Rex FeaturesNotts v Warwickshire 239-3
Good cricket all round at Trent Bridge as Dan Mousley thinks he has struck a fine boundary through mid-wicket and almost gets himself run out.
It was a terrific shot from Mousley, timed to perfection, but Calvin Harrison dived to his left to stop it and almost threw down the stumps with Mousley scrambling to get back into his ground.
Lancashire 28-0 v Hampshire 142
George Balderson has edged Mohammad Abbas but the ball dropped narrowly short of Liam Dawson at second slip.
Not a 100% convincing start to the reply. Just the eight scoring shots in the opening five overs, but five of them have found the ropes for Lancashire, a couple of them owing much to good fortune.
Phil Salt has 20 from 18 balls in his first four-day game in nearly a year.
Sussex 206-7 v Worcs
Adrian Harms
BBC Sussex
Having at one stage been 119-3, Sussex will be disappointed to reach 206-7.
James Coles with a beautifully compiled 48, and Oli Carter who eventually top scored with 76, looked to be batting Sussex into a strong position, but when Coles holed out Sussex lost three wickets for 23.
Nathan McAndrew and Carter repaired the damage with a partnership of 59, before Carter was dismissed just before tea.
Joe Leach has been magnificent in taking the17th five-wicket haul of his career, moving him up to 432 first-class wickets and joint leading wicket-taker in Division Two with Matt Potts
Durham v Glamorgan 256-4 - tea, day one
Martin Emmerson
BBC Radio Newcastle
Kiran Carlson enjoys playing Durham. His century today is his second against them this season, following his 119 in a draw in Cardiff in April. He has four half-centuries against them in varying formats too.
But it could have been so different if 19-year-old Stanley McAlindon had taken a simple catch when the batsman was on 67.
Carlson got a leading edge off a Bas de Leede ball and it looped towards the fielder, who had all the time in the world to see it coming. He'll be wondering for a long time how he managed to put it down though!
Carlson also put on 168 for the fourth wicket with Sam Northeast, who was out for 60, caught behind off Craig Miles at a point where it looked like the visitors were going to get through the whole afternoon session without losing a wicket.
Glamorgan won the toss and decided to bat and it looks like a great track to score runs on. There's also a short boundary to the eastern side of the ground, which is helping.
Essex 252-3 v Somerset
Image source, Rex FeaturesMatt Critchley gets to 50 off 45 balls at Chelmsford and also brings up Essex's first batting bonus point.
At this rate, he might get to a century before Alastair Cook, who remains on the 94 not out that he was sat on during the tea interval about half an hour ago.
Kent 217-8 v Surrey
Sean Abbott sends Jordan Cox's off-stump cartwheeling. But wait. Cox had stepped away very late in the run-up. Dead ball says the umpire, but Abbott is not impressed.
Think something behind the bowler's arm possibly distracted him.
Moments later Wes Agar flashes a nick towards Tom Latham in the slips but he can't hold on to a very sharp diving catch.
Lancashire 8-0 v Hampshire 142
Fletcha Middleton has shelled a simple catch at third slip, Phil Salt edged Keith Barker straight into his bread basket but he juggled it and dropped it.
You don't need me to tell you what Barker's face looks like.
Salt then rubs, er, salt into the wound with a back-foot punch through the covers for four from the very next delivery.