A wooden box that set the price of rice
Cut into one outer face of a small wooden box is a date: the eighth month of Ōei 3, the year 1396. The three remaining faces each carry an official title and a personal cipher, the looping hand-drawn mark called a kaō. One of them adds two characters reading daikichi, "great good fortune." The object is a masu, a box used to scoop and level grain, and for the farmers of one of Mount Kōya's largest estates it once decided how much rice they owed their landlord each autumn.
Known today as the Kōya masu, the vessel is square in plan and built of softwood, with strips of iron wrapped around its rims. This iron-bound construction is called kanabuse. The metal was not decoration. It kept the wood from splitting and held the volume steady as the box was filled and scraped clean, season after season.
A measure like this was an instrument of power. Whoever controlled the size of the box controlled how much grain changed hands. That is why three officials signed it.
The estate behind the box
The estate was Kanshōfu-shō, the central landholding of Kongōbu-ji, the great Shingon monastery on Mount Kōya. The name itself comes from the government documents, the kanpu and shōfu, by which the court once granted an estate exemption from tax. Over time the bureaucratic term hardened into an ordinary place name. The estate stretched across the Kinokawa river valley in what is now Katsuragi, Hashimoto, and Kudoyama in northern Wakayama, and the monastery on the mountain above drew much of its income from it.
In 1396 Mount Kōya carried out a kenchū, a survey of the estate's fields, to re-establish its holdings and reset what each parcel of land owed. A survey, though, was only as honest as the measure used to collect on it. Medieval Japan had no single standard for the masu. A shō in one district held a different volume than a shō in the next, and the boxes in circulation ranged from very small to very large. An estate that wished to could quietly keep one box for taking grain in and a smaller one for paying it back out, pocketing the difference. Surviving Kōyasan documents record exactly this kind of manipulation on the mountain's lands.
Fixing one authorized collection box, dated and signed by the men responsible for it, was part of putting the estate in order after the survey.
Why it is an Important Cultural Property
The Kōya masu was designated an Important Cultural Property on June 9, 1981, in the category of Historical Materials rather than fine art. Its worth is documentary. Plenty of old measuring boxes survive in Japan, but very few can be securely dated, and fewer still preserve a record of why and by whom they were made.
This one carries its own year, cut into the wood, alongside the marks of the officials who authorized it and a clear link to the 1396 survey it served. On those grounds it is recognized as the oldest surviving certified measure in Japan whose date of manufacture is known. For historians of weights and measures, it is a rare physical witness to how a medieval estate set its tax and made that decision stick.
What to look for
The inscriptions
The dated face reads, in incised characters, "Ōei, [the cyclical year] hinoe-ne, eighth month, day." The cyclical-year notation matches 1396 and confirms the reading. The other three faces name Kōyasan administrators, the sata-nin who ran the estate's affairs: the nen'yo, the gyōji, and the azukari, each followed by a kaō. The daikichi mark on one side was an auspicious blessing on the object and its work.
Iron on softwood
The box was made for hard daily use, not for display. The conifer wood is light and easy to work; the iron bands around the lip absorbed the wear of countless scrapings with a leveling stick. Look at a well-used masu and you understand its design at once. Every edge that grain touched had to stay true, because a worn rim meant a wrong measure, and a wrong measure meant a quarrel.
The companion large masu
The designation also covers a second, larger measure listed as an attached item. Medieval estates often kept boxes of different capacities for different transactions, and the survival of a matched pair adds to what the find can tell us about how grain was actually counted on Mount Kōya's lands.
Seeing it, and the country it came from
A word of honesty first. The Kōya masu is held at the Katsuragi town offices and is not on regular public display. Anyone hoping to see the object itself should contact the town in advance and ask whether a viewing or a special exhibition is possible. It is a working tax tool, not a temple treasure kept out for visitors.
The landscape it came from, on the other hand, is wide open. The box was discovered at Hōzō-ji, a temple in Katsuragi, and the whole valley below Mount Kōya still carries the shape of the old estate: terraced paddies, river flats, and the wooded slopes that climb toward the monastery. To stand in these rice fields in October, when the grain is ripe, is to see the thing the box was made to measure.
Around Katsuragi
Niutsuhime Shrine, in the highland hamlet of Amano, is the area's great draw and a registered World Heritage site within "Sacred Sites and Pilgrimage Routes in the Kii Mountain Range." By tradition its deity granted Kūkai the land on which Mount Kōya was founded, and its tower gate and main halls are themselves Important Cultural Properties. The shrine grounds are open at any hour and free to enter; the nearest rail access is Kaseda Station on the JR Wakayama Line, with a community bus running up to Amano in about half an hour.
From the valley floor in neighboring Kudoyama, the Chōishi-michi pilgrimage path climbs to Mount Kōya past Jison-in, the temple that served as the administrative seat of the Kanshōfu estate. Walking even a short stretch of it joins the two ends of this story, the land that paid the rice and the mountain that received it. Mount Kōya itself, with the monastic town of Kongōbu-ji and the vast Okunoin cemetery, sits at the head of the route.
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Q&A
- What exactly is a masu?
- A masu is a square wooden box used as a fixed measure of volume, chiefly for rice and other grain. Smaller versions later became sake cups, but the original purpose was counting: you filled the box, leveled the top with a stick, and that was one unit. This example was an official version stamped with authority.
- How do we know it dates to 1396?
- The date is cut directly into one side, giving the era name Ōei and the cyclical-year sign for what we call 1396. The signatures of the estate officials and the documented 1396 land survey support that reading, which is why the date is treated as reliable rather than approximate.
- Why would a plain box be designated a national cultural property?
- Because of what it documents. Standardized measures only spread across Japan in later centuries, so a securely dated official measure from 1396, tied to a known estate and survey, is unusually informative about how taxes were assessed in the medieval period. It was designated as Historical Materials, a category for objects that carry historical evidence.
- Can I see the box in person?
- Not as a matter of course. It is kept at the Katsuragi town offices and is not on standing display, so viewing depends on contacting the town and on any special exhibitions. Most visitors experience the context instead, through the surrounding estate landscape and the World Heritage sites nearby.
- What is its connection to Mount Kōya?
- The box was the collection measure for Kanshōfu-shō, the core estate of Kongōbu-ji, the head monastery on Mount Kōya. The rice it measured was the monastery's income, and the officials who signed it answered to the mountain. It is a tangible trace of how a great religious institution governed the land that supported it.
Basic Information
| Name | Kōya masu (with co-signed inscriptions of Kōyasan administrators, dated the eighth month of Ōei 3) |
|---|---|
| Designation | Important Cultural Property (Historical Materials) |
| Date designated | June 9, 1981 |
| Date | Ōei 3 (1396), Muromachi period |
| Quantity | 1 piece (with one attached large masu) |
| Owner | Kashiwagi district community |
| Held at | Katsuragi Town Offices, Wakayama Prefecture |
| Location | 2160 Ōaza Yōronomachi, Katsuragi-chō, Ito-gun, Wakayama Prefecture |
| Public access | Not on regular display; inquire with the town |
References
- National Database of Designated Cultural Properties, Agency for Cultural Affairs
- https://kunishitei.bunka.go.jp/bsys/maindetails/201/10155
- Kanshōfu-shō (Kii Province), Wikipedia
- https://ja.wikipedia.org/wiki/官省符荘_(紀伊国)
- Niutsuhime Shrine, official website
- https://niutsuhime.or.jp/
- Katsuragi Tourism Association
- https://www.katsuragi-kanko.jp/
Last verified: 2026.05.29