R. Yechiel Michel Tukatchinsky

Rabbi Yechiel Michel Tukatchinsky (c. 1872–1955) was a preeminent halakhic authority and calendar expert who spent most of his life in Jerusalem. He was renowned for his mastery of the laws of kiddush ha-chodesh (sanctification of the new moon) and the intricate calculations of the Hebrew calendar, publishing his magnum opus, Luach Eretz Yisrael, a comprehensive perpetual calendar with halakhic guidance. Tukatchinsky served the Jerusalem Jewish community as a respected posek (decisor) and helped establish practical standards for observing Jewish time in Eretz Yisrael. His works combined rigorous mathematical precision with deep halakhic learning, and he became a trusted guide for determining dates of holidays and fast days. He was held in high regard by both Ashkenazi and Sephardi communities in Jerusalem until his death.