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Determining Shabbos


Determining when Shabbos falls in the Far East and Pacific Ocean is subject to much halachic debate. Where  is the International Date Line according to Torah law? Why are there differences in dates in various Far East countries? Several countries, Hawaii for example, are popular vacation destinations but Shabbos may be problematic. Is it halachically recommended to spend Shabbos in East Siberia, Indonesia, Taiwan, Hawaii, Australia, Korea? Each country has its own halachic issues which will be discussed  in this article.

The Halachic Date Line

The Six Days of Creation were the first day-night cycle the world saw. Since the sun was created on the fourth day, the spot where it began its cycle and experienced its first sunset would be the Halachic Date Line. But where was the sun when it was created, and where was the first point of sunset?

The halachic day ends at sunset or when the stars become visible at any given point. But how do we determine which day it is? Since the sun is always visible at one point or another on earth’s surface, we must determine where one day ends and the next begins so the world doesn’t get stuck on one perpetual day.

Living next to the date line is technically difficult because people find it hard to live in two different days. How would it be possible to handle life if today on my side of the street it is Monday while across the street today is Sunday? Therefore, the International Date Line conveniently passes through sparsely inhabited areas, along the 180⁰ longitude. The line was twisted to accommodate various countries. When Alaska belonged to Russia, Alaska was on Russia’s side of the line and had the same day as Russia. Later, when the US bought Alaska, it was transferred to the Western side and date. The Samoa Islands, which are on the International Date Line, have changed back and forth between the dates according to residents’ demands. While the international date line is arbitrary, the Jewish holidays, and Shabbos, obviously are not.


Longitude is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth. The prime meridian defines 0° longitude; by convention the International Reference Meridian for the Earth passes near the Royal Observatory in Greenwich, England. Positive longitudes are east of the prime meridian, and negative ones are west. Jerusalem, for example, is located at 35.2⁰ E while Hawaii is between 160⁰ W – 154.8⁰ W.

Halachic Date Line

While it is well-understood why the conventional date line is located in the Pacific Ocean, there are no real objective criteria for its exact placement within the Pacific. The Halachic Date Line, in contrast, is determined according to the following halachic criteria and sources:

Jerusalem Meridian

According to the Kuzari, Ba’al Hama’or and others, the first day is the determining factor. The first day began when the sun was created on the Fourth Day of Creation, at noon over Jerusalem. Consequently, the first sunset was six hours before Jerusalem, i.e. 90⁰ east of Jerusalem. Since Jerusalem is situated on 35.2⁰ E, the Jewish date line should be at 125.2⁰ E.

Rav Tukachinsky

Another approach is that of Rabbi Yechiel Mechel Tukechinsky who rules the day begins 180⁰ from Jerusalem.

Land’s End

Another approach among the Rishonim sees the day as beginning from the farthest eastern land point – the furthets spot in east Siberia near the Bering Strait, around 169.6⁰ W, approximately 155⁰ east of Jerusalem.

This line passes almost exclusively through uninhabited areas.

Jerusalem Latitude, Eastern Land

According to the Chazon Ish, the farthest eastern spot does not refer to the farthest point on land, inhabited or otherwise, but to the farthest eastern land within Israel’s latitude. This line runs along the eastern coasts of China, near the city of Shanghai.


  1. The Kuzari and others draw the line around 125.2⁰ This line crosses mostly sea, runs east of most Chinese coasts, divides Korea from the rest of China, and leaves Taiwan, most of the Philippines, and some Indonesian islands for the next day. It splits Australia, north-east China and Siberia (in uninhabited areas). The Chazon Ish ruled this approach is the halacha and is undebatable. However, see the ensuing for how the Chazon Ish took anomilies into account.
  2. The Chazon Ish’s explanation for “the farthest eastern point” refers to the Chinese coastline at 32⁰ This line runs right through the Philippines.
  3. Other opinions see the “farthest east” as the farthest eastern point of land at the banks of the Bering Strait.
  4. Rav Tikuchinsky’s approach draws the date at 144.8⁰ W.
  5. Other opinions, the most prominent being that of Har Tzvi, define the date by direction of the first Jews’ arrival at any given locale (Radvaz I:76; Mor U’ktzia OC 344; Tiferet Yisroel, Brachos 1 and others). Cotemporary poskim disregard these opinions and only refer to the first four.

Splitting Land

What happens when the date line passes over land – could one cross over the line and keep Shabbos twice, or perhaps miss Shabbos altogether? As an example, 125.2°E passes directly through Dongfeng Street in Changchun, China. If this line of longitude were used strictly, people could simply avoid Shabbos altogether by crossing the street.

Here enters the Chazon Ish’s novel approach to determining dates: even if the date line splits a land mass, the date on the entire land mass follows the westernmost point of land. Therefore, as long as one is on the same land mass, he has the same day of that locale. Only once the land ends will the date change. A case in point: most of Australia is beyond 125.2⁰ E. However according to the above rule, Shabbos in the entire Australia from Perth to Sydney is 6 hours before Israel. Northwest China and Siberia also follow the rest of Eurasia, observing Shabbos on Saturday.

Some contemporary poskim did not accept this approach.

Practical Application

The question of the halachic date line is relevant to most Pacific islands and some neighboring countries as well:

Japan: Japan is the most debated locale among the poskim. According to the Chazon Ish and others, Shabbos is on the Japanese Sunday, and Saturday is Friday. Accordingly, all Jewish holidays fall on the next Japanese calendar date. However, for the approaches that draw the Date Line at the farthest eastern landmass or 180⁰ east of Jerusalem, Shabbos is on the Japanese Saturday.

Due to the difference in opinion, most halachic authorities agree it is preferable not to be in Japan on Shabbos and Sunday. When necessary, one should refrain from Torah-prohibited action on both days.

Northeast China and East Siberia: While beyond the Kuzari’s date line, the Chazon Ish rules they follow the rest of Asia. Most poskim agree with this approach, but some who disagree with it observe Shabbos on the local Sunday. This debate is especially relevant for the city of Harbin, China, which had a large Jewish presence between the Two World Wars. The local rabbi, Rabbi Shmuel Yosef Kisilov, wrote a lengthy discourse on the topic, concluding that the date line passes at the farthest eastern land point and Shabbos must be observed on the local Saturday. Since there was a significant Jewish presence in Harbin some contemporary poskim consider this to have the Torah status of prevalent custom as determined by eminent  halachic authorities.

Korea: While the entire peninsula of Korea is beyond 125.2⁰ E, since it follows the greater land mass (according to the Chazon Ish), Shabbos in Korea is on the local Saturday. For those who don’t accept this ruling, Shabbos should be observed on the local Sunday.

Australia: Most of Australia is beyond the 125.2⁰ E. While Australia should have been like Japan, here the Chazon Ish’s approach in which the entire land mass follows the westernmost point is the reason all large Jewish communities in Australia observe Shabbos on the local Saturday. Once the land ends, the date changes. Therefore, going on a cruise or boating trip on Sunday off the coast of Australia is problematic.

New Zealand and Papua New Guiana are halachically similar to Japan. According to the Chazon Ish Shabbos in New Zealand is on Sunday, while others see it on the local Saturday. Many poskim direct people to make an effort not to be in New Zealon Shabbos and Sunday (although Jewish communities of New Zealand observe Shabbos on the local Saturday). Some are careful to refrain from Torah-prohibited Shabbos activities on both Saturday and Sunday.

Indonesia and the Philippines: Most of the islands are certainly on the Western side of the date line, but every island must be considered individually.

Taiwan: Taiwan is west of 125.2⁰ E, as well as west of the farthest eastern land point from Jerusalem. Therefore, there’s no question regarding its date status.

Hawaii: Located between 160.2⁰ W – 154.8⁰ W, and less than 180⁰ from Jerusalem, the islands are farther than the easternmost point on land — the Bering Strait. Therefore, according to Rav Tukachinsky, Shabbos is on the local Hawaiian Friday, while according to the Chazon Ish it is on the local Saturday. Many poskim rule that in Hawaii one can be lenient and observe Shabbos only on Saturday, while some recommend being stringent.

Cruises and Flights

When flying over or sailing in the Pacific Ocean on Friday or Sunday, one must carefully scrutinize his route to ensure he doesn’t run into Shabbos at one point or another.

The Great Date Debate

The question of the halachic date line arose first when the Jewish presence in Harbin, China began growing. At its height, between the two World Wars, Harbin had a community of 20,000 Jews, consisting mainly of Russian Jews escaping prosecution. The rabbi of the city, Rabbi Shmuel Yosef Kisilov began investigating the date issue. After studying the topic at length he concluded that Shabbos should be observed on the local Saturday.

Later, when the Mir Yeshiva arrived in Kobe, Japan they sent the question to the leading halachic authorities in Eretz Yisroel. The Chazon Ish ruled that Shabbos should be observed on the local Sunday while Rav Tukachinsky maintained it should be observed on Saturday. Most refugees observed both days for Shabbos, but when Yom Kippur approached the Chazon Ish sent a telegram instructing the students not to fast on both days. Instead, he ruled they should eat on the day Yom Kippur fell on the local calendar, and fast on the following day. Most refugees followed his directives except for a select few who fasted on the first day and ate less than the prohibited amount on the following day.

To sum up the topic we must quote the Igros Moshe (OC III chapter 96): “It is very difficult to issue ruling on this matter (of dates) based on perception alone. One must rely on explicit earlier rabbinic sources for ruling.”


While I usually note sources for every halachic approach where they are mentioned, here I preferred not to mention many of the sources.

Below is a list of the sources on which this article is based. The list can serve as a reading list for further study.

The Kuzari, Mamar II:20; Hama’or, Rosh Hashana 20b; Artzos Hachaim 1; Shoel U’Meshiv IV 154; Chazon Ish OC, Kuntres Chai Shaos; Chut Shani Rosh Hashana-Yom Kippur determining that Shabbos in Japan and New Zealand is on the local Sunday; Pesher Chazon; Eretz Tzvi I:44; Sod Hanekuda Deltata; Har Tzvi OC 138; Hayomam; Yisa Yosef II: 100; Halichos Shlomo Yom Kippur 5 footnote 48; Or Letzion OC 1:14; Shevet Halevi III chapter 28; Agan Hasahar; Vaya’an Yosef 106; Mo’adim U’zmanim VI chapter 14; Tshuvos V’hanhagos I chapter 269; Imrei Shefer; Piskei Tshuvos OC 344:2.




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