Oshoro
Oshoro Stone Circles · Oshoro Jomon Hokkaido
Jomon Mid–Late 2500–1800 BCE (Hokkaido)·Jomon Hokkaido (Oshima–Shakotan)·🇯🇵 Hokkaido Prefecture, Otaru City, Oshoro neighborhood on coastal terrace at mouth of Oshoro River (Shakotan Peninsula spur), Japan
About
About Oshoro
Hokkaido Jomon stone circle (c.2500–1800 BCE Middle–Late Jomon) at Oshoro on Otaru coastal terrace — elliptical ring 30 m diameter with 47 seaside boulders and central cist, plus Fusé-gata (funnel) rock art panels on terrace edge excavated 1930s. Oshoro is Hokkaido's only large Jomon stone circle linking Honshu Oyu/Goshono/Sannai to Hokkaido's Pleistocene isolate; the circle overlooks Oshoro Bay where 200-megalithic-pit-house Kiusu-scale settlement cluster proves Hokkaido Jomon as maritime chert–jade exchange node with Sakhalin vs Honshu obsidian networks.
Why it mattersOnly Hokkaido Jomon stone circle — northern proof that Honshu Jomon ritual diffused across Tsugaru before Epi-Jomon isolation.
Open questions
Mysteries & theories
Mysteries
- 01Why single Oshoro circle vs Honshu's 14-site Jomon circle belt?
Theories
- 01Hokkaido maritime Jomon linked Shakotan jade vs Honshu obsidian; Oshoro as coastal pilgrimage focus
Theories are interpretations, not findings. The seal above tells you how much scholarly weight the place carries.
History
How it came to be
- Built
- c.2500 BCE Early stone setting; 2000–1800 BCE ring completion
- Period
- Jomon Mid–Late 2500–1800 BCE (Hokkaido)
- Culture
- Jomon Hokkaido (Oshima–Shakotan)
- Builders
- Oshoro Jomon fishers and traders
- Purpose
- Astronomical–ritual ring and cist burial focus above bay with rock art procession
- Abandoned
- c.1000 BCE Epi-Jomon re-orientation to inland pits
- Rediscovered
- 1932 Otaru schoolteacher Yamazaki reports circle; 1947–50 Hokkaido University exposure
- Excavation
- Partially excavated
c.2500–2000 BCE
Boulder transport and cist establishment
c.2000–1800 BCE
30 m final ring with 47 boulders and Fusé rock art panels
1932–50
Exposure and Hokkaido Jomon stone circle recognition as Otaru monument
On the ground
Structures & features
43.1900° N · 140.8500° E · 25 m · 2 mapped features
Elliptical Boulder Circle (47 stones 30 m)
megalithic30 m elliptical stone ring with 47 seaside greywacke boulders 60–120 cm and central cist capstone
43.1905° N · 140.8505° ERock Art Terrace with Fusé-gata Incisions
rock artCoastal terrace panel 4×2 m with fusé (funnel) incised rock art flanking circle approach
43.1895° N · 140.8495° E