Postcard from...Nagurumi Castle ruins, Gunma

 This is an outstanding preservation job on a hilltop castle (site), perched over the Tone River, in Gunma prefecture. The overgrowth has been cleared away, and the site of buildings & fortifications gentrified & identified, clearly identiable with really good signage.

Although the actual footprint of the site is quite small, it sits on a significant ridge with natural (steep!) defensive features, which were enhanced with cross-contour ditches. These have been bridged, which makes this an easy stroll of exploration. The view from the tip overlooking the valley is stunning, and I imagine this location would have been very difficult to overwhelm.

The connections with Sanada, of Ueda Castle fame, is quite something, given it's a long hour's drive around the mountains via the Agatsuma valley today and chilly enough even as spring is breaking.

This information from JCastle info:

Originally a fortification on this site was built by the Numata in defense of Numata Castle. The present fortifications date to Sanada Masayuki who fortified them to launch his attacks on Numata Castle. As an ally of the Takeda, Sanada Masayuki took control of the area by taking Iwabitsu Castle, Nagurumi Castle and finally Numata Castle in 1580. This area was heavily disputed between the Sanada and the Hojo until 1589 when Hideyoshi ended hostilities by giving the area, including Nagurumi Castle, to Sanada and the remainder to the Hojo. This decision did not sit well with the Hojo commander Inomata Kuninori who attacked and took Nagurumi Castle in late 1589. This was the famous spark that set off Hideyoshi's campaign to end the Hojo. Hideyoshi defetaed the Hojo the following year (1590) thus unifying all Japan. The Sanada were given Numata castle and Nagurumi was abandoned.

Please visit that great website for more castle info & places to explore!