Castle Atlas / No. 115
Nagurumi Castle
名胡桃城
Nagurumi Castle is Foundation list no. 115, recorded in 群馬県利根郡みなかみ町 as a 山城 site associated with 真田昌幸 and 真田氏.
History
What historically stood here
The Japan Castle Foundation records 名胡桃城 as a 山城 site in 利根郡みなかみ町, with the founding label 天正7年（1579）. The listed builder or associated clan is 真田昌幸; principal lords are 真田氏.
Today
What you are actually seeing today
The atlas currently classifies the visible condition as mountain castle ruins. Check the linked operator page for current hours, fees and restoration details.
- Current condition
- Mountain castle ruins
- Terrain
- Yamajiro: mountain castle
- Condition note
- Mountain castle with earthworks or stonework only. Classified 2026-09-24 from the structured fields at https://cmeg.jp/w/castles/1919.
Architecture And Defense
How to read the place
This record still needs feature-level reporting. For now, do not assume the most visible modern structure is the most historically important part of the castle.
Cultural-property notes in the Foundation row: 県指定史跡.
Visit
Present-day visitor information
Foundation-linked visitor source available; current hours, fees, closures and restoration information have not been republished in this first atlas pass.
- Address or access location
- 群馬県利根郡みなかみ町下津3437
- Coordinates
- 36.669873, 138.991948
- Nearest useful station
- See official visitor information.
- Estimated visit duration
- See official visitor information.
- Opening hours
- Check the official visitor source.
- Admission
- Check the official visitor source.
Nearby
Castles close enough to compare
Numata Castle
Gunma / Reconstructed gates, turrets or buildings
Iwabitsu Castle
Gunma / Mountain castle ruins
Minowa Castle
Gunma / Reconstructed gates, turrets or buildings
Kaneyama Castle
Gunma / Mountain castle ruins
Sources
Source and correction context
Identity, list membership, Foundation list number, municipality, basic classification and cultural-property notes are source-verified. Site-level visitor details require additional review unless this record is publishable. Foundation numbers are official list identifiers, not rankings. Coordinates use the Foundation-linked position-data KML and should be treated as visitor-planning coordinates rather than archaeological survey points.
Sources
- Continued Top 100 Japanese Castles, Japan Castle Foundation. Accessed 2026-09-04. Used for the official identity, list number, list membership, location municipality, castle type, founding label, builders, principal lords, and cultural-property notes for the continued 100-castle selection.
- Japan's Top 100 and Continued Top 100 Castle Position Data, Japan Castle Foundation / Nippon Castle. Accessed 2026-09-04. Used for the 200 castle addresses and coordinates exposed through the public map linked from the Japan Castle Foundation castle-search page.
- 100 Fine Castles of Japan and Continued 100 Fine Castles of Japan, Wikipedia contributors. Accessed 2026-09-04. Used only as a secondary cross-check for common English castle names; Japan Castle Foundation records remain the corpus source of truth.
- Nippon Shiro Meguri castle records: keep structure, remains and rebuilt structures, Nippon Shiro Meguri (cmeg.jp). Accessed 2026-09-24. Structured fields for each of the 200 castles, used to classify what stands at each site today. The linked record for each castle is its coordinate source.