The "Kokon Ichiyo Shu" (literally, collection of all ages, one sun) written in 1746 by Ryokin, a monk at Horyu-ji Temple, also mentions 'Kokuzo Bosatsu', indicating that 'the origin of this statue is not mentioned in ancient records, but elders tell us that it is a statue brought over from a foreign country'; this tells us that the origin of this statue was already unclear at the time.
延享3年（1746年）、法隆寺の僧・良訓（りょうきん）が著した『古今一陽集』にも「虚空蔵菩薩」とあり、「この像の由来は古記にはないが、古老の伝えるところでは異国将来の像である」と述べていて、当時すでにこの像の由来は不明であったことがわかる。