Historical artifacts that have been studied include a transverse flute kept at Shosoin, Nara Prefecture; a transverse flute which was excavated at the Shimizu Ruins in Natori City, Miyagi Prefecture (circa 9th century, Heian period), a transverse flute which was excavated at the Edaira Ruins in Tamagawa-mura Village, Fukushima Prefecture (circa 9th century, Nara period).
歴史学資料としては奈良・正倉院に伝わっている横笛や、宮城県名取市「清水遺跡」（9世紀ごろ、平安時代）、福島県玉川村「江平遺跡」（8世紀ごろ、奈良時代）から発掘された横笛についても研究されている。