Yitzchok Zev Halevi Soloveitchik (Hebrew: יצחק זאב הלוי סולובייצ'יק‎), also known as Velvel Soloveitchik ("Zev" means "wolf" in Hebrew, and "Velvel" is the diminutive of "wolf" in Yiddish) or the Brisker Rov ("rabbi of/from Brisk", (19 October 1886 – 11 October 1959), was an Orthodox rabbi and rosh yeshiva of the Brisk yeshiva in Jerusalem.

That system would become known as the Brisker method of studying the Talmud, a form of analysis stressing conceptual understanding combined with strict adherence to the text, with a special emphasis on Maimonides’ work, the Mishneh Torah.

This partly stems from his use of the Brisker method of study, in which laws are broken down into precise components, which can then be assembled into new combinations, creating novel halachic possibilities which perhaps a person should be strict to follow or avoid.

The practice is normally reserved only for areas outside the Holy Land as a memory for ancient times, when people far from Jerusalem would not hear about the declaration of the new month, and by extension would not know on which day to celebrate the holidays.

Soloveitchik was willing to eat and drink certain foods outside the sukkah, explaining that he is only stringent in areas where there is a chance that the stringency might be required by the halakha, whereas in this case, the halakhic permissiveness is unquestionable.