Shalom In our Kollel session we have been discussing the famous crossing, by ship, of the Talmidim of Yeshat Mir in 1946 from Shanghai to the U. S. A. , when Yom Kippur was kept for two consecutive days as they crossed the International Date line. What was the Psak? Were they to have had a meal at the end of the first day, then fast the entire next day? Or, as one person insisted, they fasted for a full day then were permitted to eat small amounts during the next day due to Pikuach nefesh and the extreme heat? I found a copy of the telegram on the internet, asking for the Psak, but couldn’t find the official reply.
ב"ה Shalom The question was which I'm familiar with was in regard to Talmidim from Lithuania and Poland who were in Kobe, Japan in 1941, for which occupied some of the greatest Jewish minds of the time and then many sefarim to follow. קונטרס ח"י שעות of the Chazon Ish zt"l, אגן הסהר; of Rav Aharon Chaim Halevi Zimmerman zt"l, and קו התאריך הישראלי of Rav Menachem Mendel Kasher zt"l among other publications. Rav Shlomo Yoseph Zevin zt"l' summed up the issue in his book "Le'or Hahalacha" pages 287-288. He wrote, when the question was only Shabbat, some Talmidim kept two days Shabbat out of doubt , but when Yom kippur was coming around telegrams were sent to the gedolim of Yerushalayim. The Chazon Ish said that the actual Shabbat was to be kept on the day which was held as Sunday in Kobe and that Yom kippur was to be kept on Thursday, which was a day after what Rav Tokichinsky zt"l said to keep. Eventually, the council of the Chief Rabbinate convened with other Gedolim and unanimously decided that Shabbat was to be kept on the Japanese Saturday, and Yom Kippur on Wednesday. Rav Zevin zt"l wrote, that the majority followed this ruling. All the best