This octagonal sutra container takes the form of a Treasure Banner, decoration hung up in Buddhist halls as adornment (Skt. vyūha and alaṃkāra; J. shōgon). A small glass jar shaped like a flaming jewel is mounted upon its roof-like top. The titles of eight chapters of the Lotus Sutra (Skt. Saddharmapuṇḍarīka-sūtra; Ch. Fahua jing; J. Hoke kyō) have been inscribed on the sutra container as a prayer for rebirth in the paradise of the Pure Land.
 
YOSHIZAWA SatoruEnglish by Mary Lewine 
Buddhist Art Paradise: Jewels of the Nara National Museum. Nara National Museum, 2021.7, p.346, no.66. 

This comparatively big octagonal sutra case is made of bronze in the shape of a hōtō-banner and is plated with gold. The case consists of the body, the lid, and the lotus seat. The lid is of the kabusebuta-type, and its surface is slightly raised to give it a convex shape. The shape of the lid is modeled after a flower with eight petals, and a small green glass pot, which is placed on a lotus seat and surrounded by a decoration of flaming fire, is attached onto the lid. The glass pot itself has a round lid onto which a hōju (magic jewel)-shaped knob is attached. The shoulder of the lid is rimmed in such a way that the lid fits exactly. The shape of the body of the glass pot is a rather flat sphere. It was probably a relic container brought from China during the Song dynasty.
The titles of eight volumes of the Myōhōrenge-kyō (Lotus sutra) are engraved on the upper part of the octagonal body of the container, and a prayer is engraved on the body's lower part. According to this prayer, the donator Jiin placed this sutra into the sutra case as a stupa, praying for Miroku's (Maitreya's) emergence in the future and his divine guidance. The donator also wished that he and other people would be able to enjoy divine mercy and could go to the Pure Land after death.
There is no other sutra case onto which a glass relic-container is attached, which makes this sutra case very important object. 
Masterpieces of Nara National Museum. Nara National Museum, 1993, p.138, no.112.