Magnetic Stone of Susa Takayama: Magnetised Rock on a Hilltop
The Magnetic Stone of Susa Takayama (須佐高山の磁石石, Susa Kōyama no Jishakuishi) is a scatter of strongly magnetised gabbro boulders on the summit of Mount Takayama in Susa, Hagi City, Yamaguchi Prefecture, designated a national Natural Monument in 1936.
Takayama rises northeast of Susa Bay; Yamaguchi Prefecture gives its height as 532.8 metres (the Agency for Cultural Affairs says 532 metres). According to the prefecture, almost the whole mountain is gabbro formed as magma cooled some 13 million years ago, and dark blocks of it lie across a wide area near the top. The Agency's description calls the rock quartz gabbro.
The site lies in the Takayama Minamidaira and Kitadaira districts and is owned and managed by Hagi City.
Why It Was Designated
The Agency describes the boulders as behaving like natural magnets: the closer to the summit, the stronger the magnetism, fading with distance from the top. It is rare for rock that is not magnetite to be so strongly magnetic, and that rarity is the reason for protection.
Yamaguchi Prefecture explains that a compass needle held near the Magnetic Stone of Susa Takayama is pulled toward it, and moving it just 10 to 20 centimetres can swing it right round. Even loose fragments make the needle jump.
On the cause, the prefecture says the magnetism is believed to come from the heavy currents of lightning strikes. The Hagi City Tourism Association notes that the cause is debated but mentions the view that minerals in the gabbro were magnetised by repeated strikes.
What to Look For
Bring a compass. Held near the rocks, the needle is dragged sideways, and a small shift can flip north entirely. The Agency's note that the rocks nearest the summit are the strongest is something you can test for yourself.
The Hagi City Tourism Association also tells of a post-war plan by the US military to build a radar station here, abandoned because of the magnetism. It is not backed by documentation, so treat it as local lore.
Visiting the Magnetic Stone
The tourism association says the summit is about 25 minutes by car from Susa Station on the JR San'in Line, with a car park. There are no taxis at Susa Station, so a car is the practical option. There are no fees or set hours.
As a Natural Monument, the rock must not be broken or taken away. Enquiries go to the Hagi City Susa branch office on 08387-6-2211.
Q&A
- What is the Magnetic Stone of Susa Takayama?
- A group of strongly magnetised gabbro boulders on the summit of Mount Takayama in Susa, Hagi City, designated a national Natural Monument in 1936.
- Why is the Magnetic Stone of Susa Takayama magnetic?
- Yamaguchi Prefecture says the magnetism is believed to come from the heavy currents of lightning strikes. Other explanations exist and the cause is not settled.
- What happens to a compass at the Magnetic Stone of Susa Takayama?
- The needle is drawn toward the rock, and the prefecture says moving it just 10 to 20 centimetres can reverse its direction.
- How do I get to the Magnetic Stone of Susa Takayama?
- According to the Hagi City Tourism Association, it is about 25 minutes by car from JR Susa Station, with parking near the summit. There are no taxis at the station.
- How high is Mount Takayama?
- Yamaguchi Prefecture gives 532.8 metres; the Agency for Cultural Affairs description gives 532 metres.
Basic Information
| Name | Magnetic Stone of Susa Takayama (須佐高山の磁石石) |
|---|---|
| Location | Susa, Hagi City, Yamaguchi Prefecture (Takayama Minamidaira and Kitadaira) |
| Designation | Natural Monument |
| Year Designated | Designated 1936/12/16 (Showa 11) |
| Quantity | 1 site |
| Dimensions | Mount Takayama, 532.8 metres high (Yamaguchi Prefecture) |
| Owner | Hagi City |
| Public Access | Summit area; open access, no fee |
References
- Agency for Cultural Affairs Database: Magnetic Stone of Susa Takayama (Japanese)
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/2414
- Cultural Heritage Online: Magnetic Stone of Susa Takayama (Japanese)
- https://online.bunka.go.jp/heritages/detail/139537
- Yamaguchi Prefecture Cultural Properties: Jishakuishi (Japanese)
- https://bunkazai.pref.yamaguchi.lg.jp/sp/bunkazai/summary.asp?mid=30048
- Hagi City Tourism Association: Takayama Jishakuishi (Japanese)
- https://www.hagishi.com/search/detail.php?d=100107
Last verified: 2026.09.27