Durham last week sacked their captain in response to their poor start to the season but their first day with Phil Mustard at the helm suggested it might take more than a change of leadership to solve their difficulties as Kent's Rob Key hit a brilliant double hundred.
The deposed Will Smith, who has not been selected to play at Canterbury, might have been watching developments with a wry smile as Mustard tried seven bowlers before lunch but could rely only on Steve Harmison. Harmison, still not match fit but beginning to bowl his way back into form after missing the first month of the season with a back injury, reduced Kent to 10-2 and from 127-2 to 141-4 in his first two spells.
Kent captain Key hit three sixes and 38 fours in his 261, made off 270 balls, before he was the last man out in Kent's 424.
Yorkshire, by contrast to Durham, continue to prosper. Adam Lyth struck a career-best 142 as Somerset's bowlers were made to suffer at Taunton, where there were half-centuries also for Joe Sayers and former captain Anthony McGrath as Yorkshire closed on 296-4.
Stephen Moore, Ashwell Prince and Steven Croft posted half-centuries as Lancashire reached 323-8 after deciding to bat first against Warwickshire.
In Division Two, bat dominated ball at New Road, where Daryl Mitchell (148) and Phil Jaques (92) helped Worcestershire score 376-3 against Derbyshire. Mark Ramprakash made his second first-class hundred of the season and the 110th of his career as Surrey dominated the opening day against Middlesex at The Oval while Alex Gidman and James Franklin narrowly missed out on centuries for Gloucestershire against Glamorgan.