ADIL RASHID struck a career-best 180 to help Yorkshire to 505-9 declared against Somerset at Headingley.
The leg-spinner - 120 overnight - eclipsed his previous best of 157 not out against Lancashire at Leeds in 2009.
Somerset had reached 13-0 in reply at tea, with Marcus Trescothick unbeaten on nine and Nick Compton undefeated on one.
Resuming on 371-7 after lunch, Yorkshire continued to advance through Rashid and Rich Pyrah, who added 79 in 17 overs before Pyrah was bowled by Jamie Overton for 55.
Yorkshire declared once Peter Trego had Rashid caught behind, leaving Jack Brooks unbeaten on 33.
Trego took 4-107 while former Yorkshire pace bowler Steve Kirby captured 3-119.