Hello!
While reading the chinese edition of The japanese castle games (御城碁, oshirogo) with the help of Google translate and DeepL, I sometimes come across this book - "Sitting in hidden talks" jap: 坐隠談叢, chinese: 坐隐谈丛. I failed to get much info about it. As I know, it includes smth. about japanese Go history, but maybe one has more info about it, the contents...
https://ja.wikipedia.org/wiki/坐隠談叢
The book is also mentioned here
https://ja.wikipedia.org/wiki/本因坊算砂
織田信長、豊臣秀吉、徳川家康ともに算砂に対し五子のであったと『
坐隠談叢』にある