(also known as Jakob Backofen or Back; ca. 1670–1733), rabbi, halakhic authority, and author. Probably born in Prague to a rabbinical family, Reischer studied under Rabbi Aharon Shim‘on Spira (presiding judge of the rabbinical court of Prague; 1610–1680) and Spira’s son Binyamin Volf Spira (d. 1715), the chief rabbi of Bohemia. Reischer married the latter’s daughter.
In his youth, Reischer was a Talmudic prodigy who by the age of 20 already taught his own students. Although he served as rabbi in three important Jewish communities—Ansbach (from 1709), Worms (from 1715), and Metz (from 1718 until his death in 1733)—he considered himself to be a “citizen” of Prague, where between his rabbinates in Ansbach and Worms he returned to direct a yeshiva. He did not have an easygoing personality and was party to a number of unpleasant incidents involving members of his communities.
Reischer’s erudition, intellect, and personality are evident in his most important book, his three-volume responsa Shevut Ya‘akov. Though he respected rabbis who were part of his extended family, especially his brother-in-law David Oppenheim (1664–1736), he scorned some of his colleagues and expressed strong opposition to the ordinations and numerous appointments of rabbis whom he deemed unqualified. His writings on this issue portray the tensions between rabbis and lay leaders. Reischer also made important contributions in the sphere of marriage and divorce, deciding that a court may coerce a wife-beating husband to divorce his wife—a position that was far from universally accepted. As a halakhist, he had a negative attitude toward Kabbalah. Reischer was also one of very few respondents who specifically referred to and strongly condemned the false messiah Shabetai Tsevi and his followers, known as Sabbatians.
Reischer was fundamentally against secular education and firmly believed that Jewish sources took priority over scientific answers. Though he was aware of great halakhic scholars who had studied philosophy and the sciences, and often consulted physicians, he believed that the only truth was to be found in Jewish tradition. In a comment about himself, Reischer stated that he was accepted as the final authority in halakhic matters.
Reischer’s most important works are Ḥok Ya‘akov (1696) a commentary to the laws of Passover that is included in the standard printed edition of Yosef Karo’s Shulḥan ‘arukh; his three volumes of responsa, Shevut Ya‘akov (vol. 1, 1700; vol. 2, 1719; vol. 3 [posthumously], 1789); and ‘Iyun Ya‘akov (1724), a commentary to ‘En Ya‘akov, Ya‘akov ibn Habib’s compendium of Talmudic agadot (parts of the Talmud dealing with issues other than legal matters).
Shmuel Shilo, “Ha-Rav Ya‘akov Raisher ba‘al ha-sefer Shevut Ya‘akov: Ha-Ish bi-zemano li-zemano veli-zemanenu?” Asufot 11 (1998): 65–86.