The Shach

Shabbatai HaKohen, known as the Shach (an acronym for Sifrei Kodesh—his glosses on the Shulchan Aruch), was a leading Jewish legalist and commentator of 17th-century Poland and Lithuania. Active primarily in Lublin and Vilna, he became renowned for his meticulous halakhic analysis and his monumental supercommentary on the Shulchan Aruch of Rabbi Joseph Karo, which sought to harmonize Ashkenazi and Sephardi legal traditions. His glosses—the Nekudot HaKesef on the Yoreh Deah and other sections—became standard references in Jewish legal study and are printed alongside the Shulchan Aruch in most editions. The Shach was influential in establishing rigorous standards of textual criticism and logical argumentation in halakhic discourse.