Matsumoto Castle: AKA The History Weenie Strikes Again
A random note that I came across while researching the vengeful spirit of a teapot: Matsumoto Castle as it appears today wasn't built until 1597, some 24 years after Takeda Shingen had been killed. So I am dubious that, in MoB, when Sanjou-no-kata makes a comment about "that's our Fukashi Castle" she should have recognized that was where Fukashi-jou once was. This probably also explains the ghost-of-Shingen's comment about wiping away the castles "wrong history". (A comment which I've always found really odd, since as far as history goes, Matsumoto Castle is pretty light on it. This probably contributed heavily to it being the oldest extant original construction Japanese Castle. Lots of history in Japan frequently becomes lots of destruction, and lots of lost or reconstructed castles.)
Matsumoto Castle, by the way, was only a Takeda possession for about 20-odd years. It was originally built by the Ogasawara in 1505. They held it until the Takeda took it in 1549. After the Takeda got their butts kicked (Shingen's son and heir Katsuyori was nowhere near as brilliant a general as his father; in fact, he was relatively inept) the castle went to a variety of different owners.
Randomly, while researching when Sanjou-no-kata died (1570, or some three years before Shingen), I noticed that her and Shingen's eldest daughter married Hojo Ujimasa. Ujimasa is Saburou Kagetora's eldest brother -- you know, the one who, in MoB, thought that sticking his little brother's soul into a tree was a good idea? Yeah, him. Sengoku Japan quickly becomes a very, very small world.