Paul Yachita Tsuchihashi (土橋 八千太, Tsuchihashi Yachita; 4 December 1866 – 3 March 1965) was a Japanese Roman Catholic priest, mathematician, astronomer, Sinologist, lexicographer, academic and administrator. Father Paul is known for having developed extensive tables for converting traditional Japanese era dates into Gregorian calendar equivalents — compare, e.g., Calendrical Time Conversion Table which is derived from a formula for determining the numbered date in the Japanese month.
Source: “Paul Tsuchihashi”, English Wikipedia (CC BY-SA 4.0), excerpt