Yorkshire turned the screw on Somerset after reducing the Specsavers County Championship leaders to 76 for four on the second day at Headingley.
The hosts ended the day with a 444-run lead after posting 520 in their first innings thanks to centuries from Tom Kohler-Cadmore (102) and Harry Brook (101) and 72 from Keshav Maharaj.
In reply Somerset lost four wickets in 18.5 overs as Duanne Olivier, Matthew Fisher and Maharaj all struck before stumps.
Second-placed Essex are poised to take advantage after taking a 157-run lead with nine second-wicket innings remaining having dismissed Warwickshire for 161.
The visitors were in early trouble at 33 for four and they never properly recovered as only four players reached double figures with Tim Ambrose top-scoring with 38.
That left the hosts with an 84-run advantage on first innings and they extended that, for the loss of one wicket, through Nick Browne (38) and Alastair Cook (34 not out).
Joe Denly hit an unbeaten 138 as Kent responded to Hampshire's 409 for nine declared by posting 319 for three, sharing a 202-run third-wicket stand with Daniel Bell-Drummond (94).
Hampshire added 69 to their overnight score for the loss of three wickets as Darren Stevens finished with five for 68 after removing the last two batsmen for nought.
Bottom side Nottinghamshire already find themselves up against it after being skittled for 116 in response to Surrey's 240 on a day when 16 wickets fell at Trent Bridge.
Ravi Ashwin followed up his six wickets with a top-score of 27 but the hosts still trailed by 124 and finished the day 308 behind after Amar Virdi claimed career-best figures of eight for 61.
Ashwin took his match tally to 10 with four for 64 as Nottinghamshire claimed seven wickets but Jordan Clark remains unbeaten on 43 off 61.
Division Two leaders Lancashire look like strengthening their position at the top after taking a 352-run lead over Sussex having posted 494 for six declared.
Resuming the day 149 for one, Dane Vilas top-scored with 106no after the foundations had been laid by Rob Jones (88), Alex Davies (72), Keaton Jennings (65) and Glenn Maxwell (59), leaving Sussex to reach 15 without loss in their second innings.
Second-placed Glamorgan saw their chances of closing the gap reduced after falling 402 runs behind after being bowled out for 171 with Tom Helm (five) and Toby Roland-Jones sharing nine wickets.
Middlesex, after scoring 384 in the first innings, finished the day 189 for five with Sam Robson 73no.
Temba Bavuma hit 134 in Northamptonshire's 342 on day one at Chesterfield as Matt Critchley took four wickets, with Derbyshire 34 for one at the close.
A 115-run seventh-wicket stand between Ned Eckersley (50) and Ben Raine (78no) handed Durham the advantage over Worcestershire at Chester-le-Street.
The pair resumed the day on 122 for six and guided the hosts to 212 before Raine helped Chris Rushworth (four for 28) bowl out their opponents for 151.
An unbroken opening stand of 26 saw Durham stretch their advantage to 87.