Extremely active Sun from 1190 to 1220 in the Medieval Period: Intercomparison of historical records and tree-ring carbon-14. - Miyahara H; Kataoka R; Yamamoto K; Tokanai F; Moriya T; Takeyama M; Sakurai H; Ohyama M; Horiuchi K; Hotta H (Proceedings of the Japan Academy. Series B, Physical and biological sciences, 2026)