Jinka refers to suspicious fires which often happened from the late 8th century to 10th century, mainly centering on kanga (government office) in Togoku (the eastern part of Japan, particularly Kanto region).
神火（じんか/しんか）とは、8世紀後半から10世紀にかけて、主に東国の官衙を中心に頻発した不審火のこと。