Commentary of every game available at top of this page
Northants-Glos called off because Northants player tests positive for Covid-19
Rory Burns captains Surrey, Jack Leach (Somerset) & Zak Crawley (Kent) also in action
Lancashire opener Keaton Jennings out for golden duck
All 18 counties split into three regional groups of six
Each side playing final group game; two teams with most points contest five-day final
Central Group top two, Worcestershire and Somerset, meet at New Road
North Group leaders Derbys at Lancs, second-placed Yorks host Leics
Essex, Kent, Middlesex and Hants in contention in South Group
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And we're off!
They were so keen to get out there at Chelmsford in fact between Essex and Middlesex that they started a couple of minutes early and Jamie Porter's already sent down four balls of the first over.
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As ever, we'd love to hear from you throughout this Bob Willis Trophy round.
Who do you think we'll be the two sides in the Lord's final later this month?
Also, which young players have also caught your eye for their performances in this competition so far?
Let us know using #bbccricket
As ever, every ball or every game from this closing round of the Bob Willis Trophy group stage is brought to you live by our colleagues on BBC local radio on both the BBC Sport website and app.
Find your match of choice by searching through the live coverage options at the top of this page.
There's also live commentary from 10:25 BST on BBC Radio 5 Live Sports Extra from New Road until 14:00 BST as Worcestershire take on Somerset.
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Fingers crossed we're in for a largely interruption-free day's play on the weather front.
Should be plenty of early September sunshine to see us through Sunday according to the forecast from the BBC Weather Centre.
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South Group standings
Image source, .And finally, the South Group.
Essex have 70 points, Kent 63, Middlesex 59 and Hampshire 54. All four, therefore, could in theory finish as group winners.
The maximum points Essex could reach would be 94, Kent could reach 87, Middlesex could reach 83, and Hampshire 78.
Essex are at home to Middlesex in the final round, and Kent are at home to Hampshire.
Got it? Luckily for you lot Adam's covering the south games today, I was always useless at maths!
Central Group standings
Image source, .Let's start with the central group. Somerset and Worcestershire are the only teams that can go through to the final in this one. They play each other at New Road with both sides knowing a big win could send them to Lord's.
A draw may also be enough for Somerset to progress.
North Group standings
Image source, .Who'd have predicted that Derbyshire would been in pole position in the North Group at this stage of the Bob Willis Trophy!
They take on Lancashire while Yorkshire, the only other team that can win the group, are at at home to Leicestershire.
Lancashire, Leicestershire and Notts can mathematically overtake Yorkshire, but they can't catch Derbyshire.
So we're into the last round of five in the Bob Willis Trophy group stage with those two spots in the Lord's final later this month still very much up for grabs.
To remind you - the two group winners with the highest points total will qualify for the final and there are five fixtures coming up over the next four days that will have a bearing on that outcome.
Stick with us and we'll try and talk you through who is in pole position before play begins.
Play starts at 10:30 BST unless stated
With it being September now, we start play half an hour earlier than the rest of the season.
Here's your full fixture list for this final round of the group stages:
North Group:
Aigburth: Lancashire v Derbyshire - start delayed due to wet outfield
Trent Bridge: Nottinghamshire v Durham - Durham won the toss and elected to bat
Headingley: Yorkshire v Leicestershire - Yorkshire won the toss and elected to bowl
Central Group:
Cardiff: Glamorgan v Warwickshire - Glamorgan won the toss and elected to bowl
Bristol: Gloucestershire v Northamptonshire - Northants won the toss and elected to bowl
Worcester: Worcestershire v Somerset - Somerset won the toss and elected to bat
South Group:
The Oval: Surrey v Sussex - play starts at 12:00 BST
Chelmsford: Essex v Middlesex - Middlesex won the toss and elected to bat
Canterbury: Kent v Hampshire - Kent won the toss and elected to bowl
County cricket never stops it seems in this most unique of summers.
We've had a feast of T20 Blast action over the past fortnight to keep us all entertained but now it's back to business in the four-day Bob Willis Trophy with places still up for grabs in a winner-takes-all final at Lord's later this month.
Welcome along to the first day of our live text and radio coverage for the next four days. Great to have you along.
Play begins in the next 15 minutes across nine matches so let's get right to it....