The Chrysanthemum Stone of Mount Sanage
The Mount Sanage Orbicular Granite (猿投山の球状花崗岩, Sanageyama no Kyūjō Kakōgan) is an outcrop of granite with a ball-like structure on Mount Sanage in Toyota City, Aichi Prefecture, which in 1931 was designated a Natural Monument.
The Agency for Cultural Affairs lists it under the criteria for the occurrence of rocks and minerals and for rock texture. Toyota City was appointed its managing body in March 1931, and the location is recorded as Kanocho, Toyota.
The designation text notes that it is popularly called kikuishi, chrysanthemum stone. The Toyota tourism association explains the name by the white, chrysanthemum-like patterns that appear in the biotite granite.
How It Formed and What It Is Made Of
According to the designation text, the Mount Sanage Orbicular Granite runs like a dyke through the coarse biotite granite that forms Mount Sanage, although it grades gradually into the surrounding rock.
The rock itself is fine-grained biotite granite containing orbs 4 to 8 centimetres across. Each has a core and a rim. The core is darker, a granular mix of quartz, orthoclase and biotite. The rim is white, with orthoclase, perthite, microcline, biotite and quartz arranged in radiating crystals, and it is this rim that makes the cut surface look like a chrysanthemum.
The orbs are spread over the whole rock face at intervals of 2 to 3 centimetres. The Agency notes that granite with such a structure is extremely rare.
What to Look For
The designation text describes an outcrop 2 to 3 metres wide and about 10 metres long, crossing a stream from north-northwest to south-southeast and exposed in the streambed and on the right bank. It names the stream as the Kagokawa, while the Toyota tourism association describes the outcrop on the Hirosawa stream on the mountainside, so the sources differ.
The tourism association says it looks best where the flowers seem to float up through the clear water. Look closely at the rock to see how each orb pairs a dark core with a white radiating rim.
Visiting the Mount Sanage Orbicular Granite
According to the Toyota tourism association, the Mount Sanage Orbicular Granite can be seen at any time and free of charge, with a free car park for 50 cars and toilets. It gives the address as Washitori, Sanagecho, Toyota.
From Meitetsu Toyotashi Station, take a Meitetsu bus to Sanage Tozanguchi and walk about 50 minutes. By car it is about 30 minutes north of the Sanage interchange on the Sanage Green Road. As a Natural Monument, the rock must not be struck or chipped. Enquiries: Toyota City cultural properties division, 0565-32-6561.
Q&A
- When was the Mount Sanage Orbicular Granite designated?
- It was designated a Natural Monument on 20 February 1931, with Toyota City as managing body.
- What is kikuishi?
- The local name for the Mount Sanage Orbicular Granite, from the chrysanthemum-like radiating pattern in its cut surface.
- How large are the orbs in the Mount Sanage Orbicular Granite?
- According to the designation text, 4 to 8 centimetres across, spaced 2 to 3 centimetres apart.
- Can I visit the Mount Sanage Orbicular Granite?
- Yes, at any time and free of charge; there is a car park.
- How do I get to the Mount Sanage Orbicular Granite?
- Take a Meitetsu bus from Toyotashi Station to Sanage Tozanguchi, then walk about 50 minutes.
Basic Information
| Name | Mount Sanage Orbicular Granite (猿投山の球状花崗岩) |
|---|---|
| Location | Kanocho, Toyota City, Aichi Prefecture |
| Designation | Natural Monument |
| Year Designated | Designated 1931/2/20 (Showa 6) |
| Quantity | Not recorded in the Agency for Cultural Affairs database |
| Dimensions | Outcrop 2 to 3 metres wide, about 10 metres long; orbs 4 to 8 centimetres across |
| Owner | Managing body: Toyota City |
| Public Access | Open at all times, free |
References
- Agency for Cultural Affairs Database: Mount Sanage Orbicular Granite (Japanese)
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/1417
- Cultural Heritage Online: Mount Sanage Orbicular Granite (Japanese)
- https://online.bunka.go.jp/heritages/detail/205533
- Tourism Toyota: Mount Sanage Orbicular Granite (Japanese)
- https://www.tourismtoyota.jp/spots/detail/48/
- Tourism Toyota: Sanage Shrine (Japanese)
- https://www.tourismtoyota.jp/spots/detail/244/
Last verified: 2026.09.27