Adil Rashid posted a career-best score of 180 as Yorkshire declared on 505-9 on the second day of their LV= County Championship clash with Somerset at Headingley.
Rashid was the top-scorer in the hosts' daunting first-innings total, to which Somerset responded by reaching 92-1 by the close of play.
Yorkshire started the day after an hour-long rain delay on 332-5 before Rashid added 60 to his overnight hundred as he combined for an eighth-wicket stand of 79 with the quick-scoring Richard Pyrah.
The visitors had dismissed Andy Hodd (27) and Tim Bresnan (0) in quick succession before lunch, but Rashid and Pyrah piled on the runs in the afternoon session until the latter was bowled by Jamie Overton for 55 off 54 balls.
Rashid was removed 20 runs short of a double-century as Peter Trego (4-107) had him snared behind the stumps by Jos Buttler, who finished the innings with five catches. The declaration followed immediately afterwards.
The Yorkshire attack set their sights on dismantling the top of the Somerset order before stumps, but opening duo Marcus Trescothick and Nick Compton kept things steady at the top of the innings.
However, Jack Brooks did make a vital late breakthrough as Trescothick was trapped lbw for 53 to end a 90-run first-wicket stand. Compton finished unbeaten on 33.