Time series change of notation appearing in historical materials

From Japanese and Asian Historical Resources in the Digital Age by The National Museum of Japanese History
Makoto Goto, Satoru Nakamura, Chifumi Nishioka, Arianti Ayu Puspita, Taizo Yamada, Yuta Hashimoto, Natsuko Yoshiga, Tatsuki Sekino, Naoki Kokaze, and Shohei Yamasaki