The inro is a container made up of tiers. From the late 16th century, Japanese men wore an inro suspended from their sash by a silk cord and a netsuke (toggle) because the traditional Japanese garment, the kimono, had no pockets. They were originally used to hold their owner's seal and ink or a supply of medicines. However, inro rapidly became costly fashion accessories of little or no practical use.

The design of the monkey, moon and water is a Buddhist theme derived from an Indian text (Japanese: Sogiritsu). According to the text, the Buddha told the story of a monkey who looked down a well and was very upset to see a reflection of the moon at the bottom. Believing that the moon had fallen into the well, the monkey urged his companions to save it. Thereupon they formed a chain by linking themselves together and hung down from a branch over the well. Under the weight, the chain broke and they all drowned. According to Buddhist tradition, the moon alludes to enlightenment and monkeys to delusion. In other words, the foolish monkey mistakes the reflection for the moon and risks its life for an illusion.