Japan's Hiroshi Iwata leads the field after posting a four-under-par 68 in the first round of the Open Championship final qualifying event in Thailand.
The 33-year-old from Miyagi holds a one-shot advantage at the halfway stage of the 36-hole tournament at Amata Spring Country Club.
Four players share second place on three-under with nine others a further shot back going into Friday's deciding round, setting up a tight battle for the four qualifying places available for Royal Liverpool in July.
Home player Prom Meesawat was one of the players to shoot 69, along with Iwata's compatriot Akinori Tani, Singapore's Dengshan Koh and Spaniard Carlos Pigem.
Americans Berry Henson and David Lipsky and Australia's Adam Groom were among the group at two-under, which also included Taiwanese amateur Cheng-Tsung Pan.
Former Open participants Mardan Mamat, at one-under, and Prayad Marksaeng and Ashun Wu at level-par were all in contention but China's Liang Wenchong was two-over.