Jamie Porter found form in the Specsavers County Championship for the first time in 2019 as Essex's formidable fast bowler helped bowl Nottinghamshire out for 187.
Porter has enjoyed incredible hauls of over 50 wickets in the previous four campaigns, which included plundering 75 wickets in 2017's title winning season and 58 last year.
But having cumulative figures of two for 276 from the opening two games, against Hampshire and Surrey, he burst into life with analysis of four for 75, which included his 250th Championship notch in a typical destruction against Nottinghamshire.
Fellow bowlers Sam Cook, Peter Siddle and Simon Harmer all chipped in with two wickets-a-piece as Essex, who finished on 69 for no loss, dominated the first day's action at Chelmsford.
Zak Crawley's unbeaten half-century put Kent in control against Yorkshire.
Having bowled the White Rose out for 210 in the opening two sessions, Crawley finished unbeaten on 73 as Kent moved to 130 for four, just 80 behind.
Matt Milnes, with three for 63, and Harry Podmore, who took two for 33, were the pick of the home attack as the visitors succumbed inside 57 overs.