Chiragh, who got himself tournament fit after a long gap during the summer months, when there were no events, has planned a few Asian Development appearances.
Also in the field are Himmat Rai (72) in tied 33rd and Feroze Ali (75) in tied 53rd.
Tournament host Thongchai Jaidee produced a 68 to lie two shots back in tied-sixth position while playing partner and reigning ADT Order of Merit champion Pavit Tangkomolprasert posted a 70 to grab a share of 23rd place.
The leading duo holds a one-shot advantage over local prospects Pannakorn Uthaipas, Thitiphun Chuayprakong and Singapore's Lam Chih Bing, who shared third place following identical 67s, at the Black Mountain Golf Club.
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Prayad, who has claimed four titles this year including a win on the Asian Tour, took advantage of the relatively calm morning conditions to extend his fine form.
All 78 players from the afternoon session, including Thai stars Kiradech Aphibarnrat, Thaworn Wiratchant and Prom Meesawat, will have to return to the Black Mountain Golf Club at 7am tomorrow to complete their opening rounds.