Mitchell Claydon claimed his best figures for Kent as Leicestershire were bowled out for 217 on a day when 15 wickets fell in the LV= County Championship Division Two game at Grace Road.
Bottom-of-the-table Leicestershire hit back by taking five wickets in the final session to leave Kent on 106-5 at the close, still 111 runs behind.
It was certainly a day for the seam bowlers, with Claydon taking 5-77 in 21 overs before Leicestershire's attack put them back into contention as they seek their first Championship win of the season.
Angus Robson top-scored for Leicestershire with 56, while Rob Taylor (37) and Jigar Naik (25) put on a useful 54-run partnership for the ninth wicket before Charlie Schreck (2-31) took the wickets of both Rob Key and Sam Northeast to boost the hosts’ fortunes.
Second-placed Hampshire were surprisingly reduced to 182-9 having made a solid start against Gloucestershire on day one at the Ageas Bowl.
Michael Carberry (39), Jimmy Adams (43) and Will Smith (45) gave the promotion chasers a decent platform, but the dismissal of Smith spaked a collapse that saw them lose five wickets for just 12 runs.
However, an unbroken tenth-wicket stand of 69 between James Tomlinson (33 not out) and David Balcombe (38no) saw the hosts to 251-9 at stumps.
Seamer Liam Norwell was the pick of the Gloucestershire attack as he finished with 4-87 including the scalps of Smith and James Vince.
Zafar Ansari's career-best century has strengthened Surrey's grip on the second day of their clash with Glamorgan at Colwyn Bay.
Ansari's patient near seven-hour innings of 112 helped Surrey towards an imposing total of 400-5 when rain caused a premature close, giving them a 168-run lead heading into day three after Glamorgan had been bowled out for 232 on the opening day.
Ansari shared in a 182-run partnership for the first wicket with Rory Burns, who disappointingly fell three runs short of his century, and another 88-run alliance with Arun Harinath (60).
After Glamorgan fought back briefly with the second new ball - Michael Hogan took two wickets in consecutive balls and Jim Allenby claimed the wicket of Ansari - Jason Roy accelerated the score with a 55-ball half-century with nine fours.
A hostile spell of fast bowling from Graham Napier put Essex back in the game after Wayne Madsen and Wes Durston had given Derbyshire the initiative on the opening day at Chesterfield.
Madsen and Durston added 146 for the fourth wicket but the game changed when Durston was hit on the side of the helmet by a Napier bouncer and forced to retire hurt for 74 on his first Championship appearance since late April.
He was taken to hospital and it sparked a collapse that saw Derbyshire lose six wickets for 49 in 109 balls and end up posting 275 - Napier claiming 3-11 in 31 including Madsen for 90 to finish with figures of 4-44.
Essex wicketkeeper James Foster took five catches but his side lost Tom Westley in the first over of their reply before they closed on 25-1, 250 behind.