One Hot-Spring Deposit, Designated by the State in 1928
Colloidal Silica and Sinter from Nakabusa Hot Springs (中房温泉の膠状珪酸および珪華) lie in Azumino City, Nagano Prefecture, and were designated by the state on 4 October 1928. The category is that of natural monuments.
The field for a managing body stands empty.
The Agency locates the springs about 10 kilometres west of a station on the railway of the time.
Of the Two in the Name, One Is Called Not Rare
The two things named are not weighed alike.
The name joins colloidal silica and sinter. Sinter is silica deposited from hot water and hardened; colloidal silica is silica still in a soft, jelly-like state.
The Agency records that the deposition of sinter is by no means rare at hot springs in volcanic districts.
It closes, however, that places where colloidal silica is being deposited, and places that show a relation between the deposition of silica and micro-organisms, have few parallels elsewhere.
At the Misaka tunnel, the record grants the plainness of the portals before stating the value: one aspect of one thing is conceded.
Here, of 2 things in the name, one is called not rare and the value is laid on the other. As a way of stating value this is the twenty-fifth met.
A Pale Purple That Points to Living Things
The colour of the deposit is taken as a sign of life at work.
The Agency records that on the ground where one spring runs off, colloidal silica of a pale purple, like cheese, is in the act of being deposited.
That it takes on a pale purple, the record continues, shows that micro-organisms are concerned in the deposition of the silica.
Something soft as cheese is still settling now; its pale purple shows living things at work in the settling.
At the okichimozuku habitat, the alga itself is the reason for designation: a living thing is the subject.
Here the subject is not a living thing but a deposit, and from its colour the part of living things is read. It stands on the line between stone and life.
More Than Thirty Springs
The places where water rises are recorded in number.
The Agency records that the outlets are very many, reaching more than 30.
It names 9 of the springs one by one, and says the deposition of sinter is especially marked around them.
The deposit extends a hundred and some tens of metres from east to west and 40 metres from north to south, and reaches 2 metres at its thickest.
At Himeshima, the island is counted as 7 volcanoes: the landform is the unit.
Here each spring carries a name of its own, and the spread of the deposit follows the ground where their water runs.
Visiting
The deposit lies in Azumino City, Nagano Prefecture.
The Agency gives the position as a distance from a railway station, under the railway's name of 1928.
At Hayabusa Station, too, the position is given as a distance from another station: a manner of placing things by the railway.
The commentary is written in the old written language, like the first part of the Yame record: the text of the time of designation remains as it was. The name and the commentary even use different characters for silica.
The deposit lies on the ground of a hot-spring establishment, so whether and how it may be visited follows the owner's and the local authority's arrangements. Check before travelling.
Q&A
- When was it designated?
- On 4 October 1928, by the state. The category is that of natural monuments.
- How do sinter and colloidal silica differ?
- Sinter is silica deposited and hardened; colloidal silica is silica still soft and jelly-like, described here as like cheese.
- What is valued in it?
- The record grants that sinter is not rare, and says that places depositing colloidal silica, and places showing micro-organisms at work in the deposition, have few parallels.
- Why is it pale purple?
- The Agency says the pale purple shows that micro-organisms are concerned in the deposition of the silica.
- How far does it extend?
- A hundred and some tens of metres from east to west and 40 metres from north to south, 2 metres thick at its thickest.
Basic Information
| Name | Colloidal Silica and Sinter from Nakabusa Hot Springs (中房温泉の膠状珪酸および珪華); the commentary uses a different character for silica |
|---|---|
| Location | Azumino City, Nagano Prefecture |
| Designation | Natural monument; designated as a natural geological phenomenon rather than as a building or a work of art |
| Year Designated | 1928 (4 October), designated |
| Quantity | 1 site; the outlets number more than 30 |
| Dimensions | The sinter extends a hundred and some tens of metres from east to west and 40 metres from north to south, 2 metres at its thickest. The position is given as about 10 kilometres west of a station on the railway of the time |
| Owner | The field for a managing body stands empty in the record |
| Public Access | On the ground of a hot-spring establishment; visiting follows the owner's and the local authority's arrangements |
References
- Cultural Heritage Online: the silica deposits at Nakabusa
- https://bunka.nii.ac.jp/heritages/detail/210170
- Agency for Cultural Affairs, National Cultural Properties Database
- https://kunishitei.bunka.go.jp/
- Hachijuni Culture Foundation: cultural properties of Shinshu
- https://www.82bunka.or.jp/bunkazai/detail.php?no=1543
- Azumino City
- https://www.city.azumino.nagano.jp/
Last verified: 2026.09.21