England's Matthew Southgate moved into an early lead as the Aberdeen Standard Investments Scottih Open began at Gullane.
The 29 year old followed a birdie on the first with an eagle on the par five second, with further gains on the eighth and ninth seeing Southgate turn in 30.
At five under par he was one clear of Dane Lasse Jensen, German Marcl Siem, France's Matthieu Pavon, South African Richard Sterne and English pair Robert Rock and Matthew Fitzpatrick.
Americans Rickie Fowler and Kevin Chappell were among those on three under during the early stages of the year's fifth Rolex Series event.
Defending champion Rafa Cabrera Bello, last week's winner Russell Knox and major champions Patrick Reed, Danny Willett and Martin Kaymer were among the later starters.