Seventeen wickets tumbled on an eventful opening day as Northamptonshire hosted Yorkshire in LV= County Championship Division One.
Ian Butler took four wickets as Yorkshire were inserted to bat at Wantage Road and then bundled out for just 136 in 40.3 overs.
Northamptonshire then fared moderately better, thanks to 70 from James Middlebrook, as they reached 191 for seven before the close.
Yorkshire's day began badly as Adam Lyth was removed lbw for a duck with just four runs on the board, as Maurice Chambers took the first of two scalps.
Lyth was one of three Yorkshire batsmen to fail to trouble the scorers, with captain Andrew Gale and Tim Bresnan - allowed to play after being released from England duty - also falling for nought, both to Butler.
Yorkshire lost wickets at regular intervals but new signing Aaron Finch offered hope of a revival, hitting four fours and a six on his way to a top score of 34.
His efforts were ended when he played on to Azarullah to leave Yorkshire 95 for seven in the afternoon session.
Azarullah went on to claim respectable figures of three for 41 but it was Chambers who finished the innings when he ended Liam Plunkett's late resistance following a run-a-ball 25.
Yorkshire reprieved Middlebrook early in Northamptonshire's reply when he was dropped by Finch on 10 off Bresnan.
Jack Brooks made the first breakthrough when he had captain Stephen Peters taken at slip by Alex Lees following an opening stand of 44.
Brooks (four for 58) then snared David Sales, Matthew Spriegel and Rob Keogh in quick succession to reduce Northants to 90 for four at tea.
Middlebrook batted on to reach his half-century off 70 balls, with nine fours, but he survived a scare on 59 when Lyth was unable to take a difficult chance at second slip.
Bresnan (two for 54) trapped Rob Newton leg before to end a promising fifth-wicket stand of 39 with Middlebrook, whose luck then ran out when he edged the same bowler to Finch at slip.
After a stoppage for bad light in the evening, Plunkett then removed Andrew Hall lbw before the close, leaving Ben Duckett and Butler looking to extend a lead of 55 on Sunday.