All 18 counties play on opening day of 2021 County Championship season
Teams split into three groups of six
Defending champions Essex host Worcestershire
England Test captain Joe Root plays for Yorkshire
Listen to ball-by-ball BBC local radio commentary from all nine games
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Balbirnie lbw b Patterson 16 (Yorkshire v Glamorgan 29-3)
Glamorgan three down now as the testing batting conditions continue at Headingley.
Andy Balbirnie is trapped leg before by a beauty of a nip-backer from veteran seamer Steve Patterson for his first scalp of the season.
Billy Root is the not out batsman at the other end.
Group 2 update
England's Ollie Pope has come in at four for Surrey today. Former South Africa batsman Hashim Amla is aiding Surrey's recovery with the 23-year-old - they're now 31-2 against Gloucestershire.
Hampshire are building a solid platform at Leicestershire - Joe Weatherley and Ian Holland have taken them to 36-0.
Just a reminder that this is the group that also contains Middlesex and Somerset. Might take a bit of getting used to, this new format, but we'll get there!
Essex 23-0 v Worcestershire
Image source, Rex FeaturesSteady accumulation continues for Essex openers Alastair Cook (8 not out) and Nick Browne (12 not out) at Chelmsford.
First 10 overs of the day sent down by the Worcestershire seamers who are getting the odd ball to keep low and nip around but no breakthrough as yet for the Pears.
Middlesex 31-1 v Somerset
Image source, Getty ImagesSam Robson looks in good touch.
The Middlesex opener is up to 23 at a run a ball including a nice clip off his legs for four in the last over.
Nick Gubbins has joined the former England man in the middle after the early loss of Max Holden.
Group 1 update
Image source, PA MediaAs one of our tweeters just mentioned there, Nottinghamshire have claimed a couple of early scalps against Durham at Trent Bridge.
Jake Ball has accounted for opener Michael Jones and returning Durham skipper Scott Borthwick already to leave them 9-2.
At Edgbaston, there's also been a couple of early wickets for Warwickshire against Derbyshire.
Billy Godleman and Anuj Dal (above picture) already back in the pavilion with Liam Norwell taking both scalps. Derbyshire 3-2 the latest there.
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Toaster Philp: Lots going on at Edgbaston, not least the chilly wind blowing across the car park!
John Smith: Matt Parkinson really can't get a game at the moment
Gareth Hern: Durham 5-2 already, after winning the toss. Welcome back cricket, it's like you've never been away
Group 3 update
Sussex are playing their 'home game' against Lancashire at Old Trafford today after the Hove outfield fell victim to a bug infestation over the winter.
And they've lost an early wicket - Aaron Thomason the man to go, bowled by Saqib Mahmood. Sussex are 5-1.
Daniel Bell-Drummond and Jordan Cox are ticking along nicely for Kent at Northants - they're 10-0.
Image source, Getty ImagesGroup 2 update
England and Surrey opener Rory Burns is out for just four against Gloucestershire. The left-hander drove loosely at an outswinger from David Payne and was gobbled up in the slips. Mark Stoneman is also gone and Surrey are 12-2.
Hampshire have made a solid start at Leicestershire through openers Joe Weatherley and Ian Holland - they're 20-0.
Lloyd b Fisher 4 (Yorkshire v Glamorgan 12-2)
Another early wicket for Yorkshire.
Matthew Fisher in the action this time as he gets one to jag back from outside off and embarrass David Lloyd.
He misjudges the leave and unfortunately for him hears the rattle of his off stump behind him.
Holden c Banton b C Overton 4 (Middlesex 17-1 v Somerset)
Breakthrough for Somerset in the third over at Lord's.
Max Holden is late on a pacy delivery from Craig Overton and gets an inside edge onto his pad - the ball loops to Tom Banton at square leg.
Image source, Getty ImagesSelman b Coad 4 (Yorkshire v Glamorgan 8-1)
Overcast morning at Headingley and Yorkshire's seamers bag an early wicket inside the first five overs.
Glamorgan opener Nick Selman sees his stumps rearranged by a neat bit of bowling from the metronomic Ben Coad and departs for just four.
Most likely the first of many scalps for the tall right-armer this season.
Essex 5-0 v Worcestershire
Image source, Rex FeaturesWatchful start from champions Essex after winning the toss and electing to bat first against Worcestershire.
Nick Browne has struck the one scoring stroke of note so far with a neat back foot drive through the covers for four off Dillon Pennington.
Alastair Cook yet to get off the mark in the first four overs.
Middlesex 13-0 v Somerset
They're under way at Lord's after a 10-minute rain delay and Sam Robson has taken 13 off Craig Overton's first over, including a couple of handsome drives to the boundary.
Hello, and welcome to the new season Craig.
Northamptonshire 0-0 v Kent
Andrew Radd
BBC Radio Northampton at Wantage Road
Bright but chilly at Wantage Road - and everyone pleased to be back on duty.
Adam Rossington has won the toss and put Kent in to bat. Northamptonshire leave out seamer Jack White and spinner Simon Kerrigan from their 13, while Kent omit Fred Klaasen and Marcus O'Riordan.
Tom Taylor makes his Championship debut for Northamptonshire - becoming the club's 529th first-class player.
Warwickshire v Derbyshire 0-1
It's come at Edgbaston where Liam Norwell has removed Derbyshire captain Billy Godleman for nought.
Middlesex v Somerset - start delayed, rain
Told you that rain shower would move through quickly... they'll start in five minutes at Lord's.
Nottinghamshire v Durham 2-0
Martin Emmerson
BBC Radio Newcastle at Trent Bridge
It's a chilly old day at Trent Bridge with beanie hats very much the fashion accessory of the day - during the warm-ups anyway.
Notts and Durham both finished the Bob Willis Trophy campaign here with a draw last year, 211 days ago. It meant both went through their shortened five-match campaigns without a win.
Durham have been slow starters in recent seasons but must think there is no better opportunity to get an early win under their belts this time, as they meet a side who are winless in their last 27 championship matches!
They are also led by Scott Borthwick for the first time following his return to the club after a "four year holiday in London" - so claimed coach James Franklin last night!
For their part Notts are no doubt thinking it's time to put an end to that run of winless games which stretches back to 23 June, 2018 at Chelmsford.
Middlesex v Somerset - start delayed, rain
A rain shower is passing over Lord's, so they're not going to start on time. How frustrating.
It should move through pretty quickly though.
The 2021 County Championship season is under way!
Image source, Getty Images#bbccricket
The plan today is to keep a close eye on the games between Essex and Worcestershire, Middlesex against Somerset and Yorkshire versus Glamorgan.
Plus we'll bring you regular updates and all the key moments from the other six matches.
We'd like you guys to get involved to - using #bbccricket on Twitter - and we'll publish a selection of your comments throughout the day.