This set of votive offerings was excavated from behind the Ubusuna Jinja Shrine within the precincts of Kokawadera Temple. An inscription on the parasol-shaped lid of the bronze inner container tells us that the ceramic outer container in which it has been placed was fired at the Sanage kilns in Aichi prefecture. Sutra mounds reflect practices of Maitreya faith: one prays to forge karmic ties with the bodhisattva Miroku (Skt. Maitreya), the Buddha of the future, through the merit one creates by copying out The Lotus Sutra (Skt. Saddharmapuṇḍarīka-sūtra; Ch. Fahua jing; J. Hoke kyō) while keeping the precepts, and then burying it at a sacred site.
 
YOSHIZAWA SatoruEnglish by Mary Lewine 
Buddhist Art Paradise: Jewels of the Nara National Museum. Nara National Museum, 2021.7, p.346, no.64. 

The objects introduced in this article were excavated from the southern slope of Mt. Fūmō-zan in the northern part of Wakayama prefecture. The well-known Kokawa-dera temple is located at the foot of this mountain. It is reported that the bronze sutra case, which contained eight volumes of the Hoke-kyō (Lotus sutra), was placed in a cylindrical case made of ceramics, and the case was covered with a plate of natural rock. The sutra case was cast in bronze and a ball-shaped knob is attached to the lid. Nine lines of inscription are engraved on the surface of the cylindrical outer case. According to the inscription, the learned scholar Kiyohara-no-Sanetoshi promoted the project of burying sutra scrolls: he had the Hoke-kyō sutra copied by six priests at Serio-bessho temple in Ōhara, Kyoto, and buried the sutra scrolls at Kokawa-dera temple, wishing for the encounter with Miroku-bosatsu (Maitreya) in the future. According to the old record Honchō Shinshū Ōjō-den, Sanetoshi copied the Hoke-kyō sutra and sent copies to local famous temples.
The shape of the sutra case introduced in this article is excellent and the sutra volumes are well preserved, considering of the fact that they had been buried underground. The ceramic outer case was probably made in some old kiln in Aichi prefecture. 
Masterpieces of Nara National Museum. Nara National Museum, 1993, p.136, no.110.