godan verb (-ru), intransitive verb
catch fire; start burning; burn merrily
Typically used for charcoal or firewood catching fire and burning well. Often implies a lively, steady flame. The kanji 熾 is uncommon.
炭がやっとおこった。
The charcoal finally caught fire.
火がよくおこって、部屋が暖
The fire started burning well and the room became warm.