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On the Edge: The International Date Line in Halacha

An Overview of a Shiur by Rav Yosef Greenwald for Parshas Tazria/Parshas HaChodesh

(החודש הזה לכם ראש חדשים (שמות יב:א

Where is the Date Line located according to halacha? Three basic approaches are offered. 

  • Chazon Ish   
    • 6 hours (90 degrees) ahead of Yerushalayim, which runs through Siberia, part of China, and part of Australia (though land masses are not divided in his opinion).
    • Based on the Baal HaMaor (to Rosh Hashana) concerning kiddush hachodesh.
    •  Shabbos in Japan is observed on Sunday.
  • Rav Tuchachinsky
    • 12 hours (180 degrees) ahead of Yerushalayim, which runs through part of Alaska and the Pacific Ocean to the left of Hawaii.
    • Based on the idea that Yerushalayim is the center of the world
    • Shabbos in Hawaii is observed on Friday.
  • Rav Tzvi Pesach Frank/Rav Ovadia Yosef
    • We follow the regular International Date Line.
    • Since the Gemara doesn’t address directly, we should follow the local custom.
  • Practical Halacha Today
    • Most poskim do not take a definitive stand on the issue.
    • Therefore, many poskim suggest for Shabbos to keep Shabbos on the local Saturday and be machmir for melacha deoraisa on the other day.
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