Nine games across Divisions One and Two
In Division Two, promotion-chasing Yorkshire dismiss Leicestershire for 98 in one session
Division One's top two meet at Taunton as leaders Surrey visit second-placed Somerset
Tom Banton hits century for Somerset but they lose final five wickets for just 12 runs as Surrey debutant Shakib Al Hasan takes 4-97
That brings to a close our coverage of day one.
Some very interesting scoreboards around the country and tomorrow could bring some key moves in the title, promotion and relegation races.
Join us in the morning.
Essex 262-5 v Notts
Instead of blocking out the day, Michael Pepper sends one into the Tom Pearce Stand with three balls to go.
But this has been Tom Westley's day.
The Essex captain is unbeaten on 108 overnight with a high-quality century.
After an indifferent top-order performance left Essex 86-4, it needed Westley and Paul Walter (72) to put on 142 and give the hosts the ascendancy.
Durham v Lancs 177-6
Matty Hurst is back and across to Colin Ackermann, working the off spinner into the covers for two.
He gets one more off the fourth ball, slapped to backward point.
Two slips in for Tom Hartley, who tries to force the fifth ball down the ground on the back foot and smothers the last one with a forward block.
Slow going for Lancashire, who have just about been kept in the contest by Matty Hurst, who has put on 39 in 153 balls with Hartley and remains unbeaten on 74 not out.
The Red Rose will have to try and go up a gear tomorrow to keep the pressure on Notts, who hold a slender advantage just above them in the relegation zone.
Essex 254-5 v Notts
Liam Patterson-White bellows out a couple of loud appeals for a caught behind that does carry and an lbw. He's done for the day.
Fahan Ahmed will bowl the last over of the day.
Leics 98 v Yorks 263-8
A huge day for Yorkshire's promotion hopes.
They won a crucial toss this morning and bowled first on a pitch that did all sorts with the new ball.
Leicestershire didn't help themselves at times but Yorkshire were very disciplined with the ball and Ben Coad returned figures of 10-6-15-5.
The Foxes crashed to 15-7 and were in danger of setting some unwanted records before Ben Cox got a few away and made 51 not out to avoid complete humiliation.
But they were still fired out for just 98 in only 24.2 overs.
Yorkshire wobbled themselves at 56-4 and at 142-6, their lead was only slender.
But Jonny Tattersall has played a wonderful innings to steer his side into what should now be a match-winning lead.
He walks off 90 not out, the toast of the Broad Acres.
Essex 251-5 v Notts
A batting point for Essex.
Michael Pepper strolls through for a simple single and that is 250 on the board and a point.
Durham v Lancs 174-6
A switch of ends from Callum Parkinson, now coming in from the Lumley End.
Tom Hartley leaves the ball, bowled from round the wicket with a bit of width outside off. Maiden over.
Colin Ackermann will bowl the last over of Day One.
Durham v Lancs 174-6
A short spell for the occasional spin of Colin Ackermann, who tosses the ball up to Tom Hartley with one slip in place.
Hartley pushes a single into the leg side.
Matty Hurst tries to work the ball away off side on the back foot and then gets forward to the next one to block.
Two overs left tonight.
Northants 219 v Derbyshire 65-1
Derbyshire firmly on top after day one of the battle between the second tier's bottom two sides.
A collective effort from the basement team with seven bowlers taking wickets to dismiss Northants for 219, Saif Zaib's 90 the highlight for the hosts.
Derbyshire lost Harry Came early in their reply but Luis Reece (39no) and Brooke Guest (20no) got through the remainder of the evening session unscathed.
Essex 236-5 v Notts
Kyle Verreynne is the only person at Chelmsford who thinks he's stumped Michael Pepper.
It was a wild sweep missed by the batter, and then the bails are dislodged.
Verreynne runs towards the square leg umpire convinced he should have a wicket.
Actually, the replay shows the South African is probably right. Hard to tell 100 per cent but Pepper's back foot was high in the air.
Essex 241-5 v Notts
Tom Westley isn't done with just a century.
He sweeps Farhan Ahmed, gets enough on it to take it fine and to his eighth boundary of this crucial innings.
Six overs to go.
Leics 98 v Yorks 251-8
In the context of today's cricket, this is a miracle innings from Jonny Tattersall.
He's onto 88 not out - and it's been a vital knock to ensure Yorkshire didn't waste their good work with the ball earlier.
A batting point is raised and four overs are left in the day.
Middlesex 377 v Gloucs
Tom Price ends the day with a deserved haul of 5-81 in 21.2 overs.
Henry Brookes is last out for a second-ball duck, stuck on the crease and fencing a ball that seams away, edging to keeper James Bracey.
An absorbing contest ends with Middlesex perhaps slightly the happier of the two sides after fluent knocks from Mark Stoneman (42) and Max Holden (77), followed by a thrilling counter-attack from Jack Davies (91) and Josh de Caires (64) - who put on 120 for the sixth wicket.
Gloucestershire rarely bowled badly and will rue an edge or two which didn't quite carry to slip.
Durham v Lancs 170-6
Tom Hartley is forward to Bas de Leede, defending into the off side.
Hartley sways out the way of a bouncer and defends a slightly fuller ball on the up.
A couple of plays and misses outside off in a tense over, which ends with Hartley digging out a yorker.
Essex 236-5 v Notts
Image source, Rex FeaturesBrought up with a FIVE!
Tom Westley dabs into the leg side and sets off. Haseeb Hameed shies at the stumps to run Michael Pepper out.
It only just misses and runs away for four overthrows.
A 28th First Class century for Westley. A top effort from the Essex skipper.
Essex 228-5 v Notts
Nottinghamshire will be relieved the light improved.
Paul Walter is caught off the bowling of Farhan, trying to hit a big one off the spinner and Liam Patterson-White keeps his eyes on the ball as it descends from the skies.
Image source, Rex FeaturesMiddlesex 374-9 v Gloucs
Toby Roland-Jones is moving up a gear or three here.
He flays a short ball from Zaman Akhter square for four and gets four more smashed through cover point.
And now he's out!
Akhter pitches it up and the ball flies into the stumps via the inside edge as the Middlesex captain goes for a flashing drive.
A loose shot with 400 possibly on the cards.
Henry Brookes is the Middlesex number 11.
Sussex 121-1 v Glamorgan 186
Indeed we won't see those two overs today, as another top Sussex day ends.
Glamorgan reached 186 - largely due to Kiran Carlson's excellent 56 and Dan Douthwaite's patient 41.
At the time it looked a middling score, with the batting clearly not easy against the moving ball but Dan Hughes and Tom Haines saw out the new ball trouble.
They put on 110 before Haines edged to first slip but only trailing by 65 at close one down is a good position to build a commanding position tomorrow and beyond.