Most of the earthen images were produced in the Nara period and few were produced in Heian period or later (mainly after 9th century) when wood carvings became the mainstream in sculpture society.
日本では、塑像の作例は奈良時代に集中しており、木彫が彫刻界の主流となった平安時代以降（おおむね9世紀以降）の塑像の作例はまれである。