Now to the place where historical Kagetora died: the sight of Samegao castle.
Again, this place is mentioned more than once, and in vol. 5 prologue Kagetora has a dream about the siege of Samegao:
Samegao Castle was strategically placed on the Shinetsu border. Horie, the master of this castle, had been a trusted ally. He had fled Echigo only to be betrayed at the very last. The Echigo border was just beyond the castle. He would probably be able to throw off his pursuers if he could cross over the mountains. But Kagekatsu’s massive army had already completely surrounded the castle and reduced the land around it to ashes.
He cast his gaze across the Echigo plains. He could see a small light in the distant north—the light of the lands around Kasugayama? He closed his eyes tightly.
Samegao castle stood on a hill overlooking the flatlands of Echigo. Now there's nothing there, just a pretty view. On a clear day you can see the sea in the distance, and also the hills where Kasugayama castle stood (I was surprised how close it is; Kagetora could have really seen the lights).