Ruins of castle in Niwase in Okayama

I went to my father's home in this long holidays. I got off the train at the last station Niwase. And I walked around there and watched the ruins of castles.
The reason why I do so was that I found many small lakes and short rivers near the station on google's map.
Small lake was appeared as soon as I got off the train and walked. It was beautiful sight. It was ruins of castle Niwase.