The latter theory of originating from Busshari already appeared in a description in Hizoki (an early Shingon text) that 'each grain of rice is called shari in India. Busshari also looks like a grain of rice. Therefore, it is called shari.'
後者の仏舎利を語源とする説も、秘蔵記に於ける「天竺呼米粒為舎利。仏舎利亦似米粒。是故曰舎利。」という記述で既に現われている。