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The Sabbath, the International Date Line and Jewish Law

The Sabbath, the International Date Line and Jewish Law

How does the change in Samoa affect Sabbath for the local Jews?


Dear Rabbi,

Now that the Pacific island of Samoa has changed from the east side of the International Date Line to the west—to be in sync with Australia and New Zealand, its main sources of tourism and business—I’ve been wondering if there are any implications in Jewish law.

When will Samoan Jews and Jewish tourists observe the Sabbath?


You ask a good question. Jews worldwide celebrate the Sabbath, or Shabbat, on the seventh day of the week. But what happens when a country skips a day and changes their Friday to Saturday?

The concept of a date line, and the fact that a traveler would either gain or lose a day after circumnavigating the globe, had been discussed in Jewish works hundreds of years before the establishment of the International Date Line.

In fact, the first to articulate the need for a date line was the Jewish philosopher Rabbi Yehudah Halevi (1075–1141), in his classic work, the Kuzari.1

History of the International Date Line

In 1884 Greenwich, England, was chosen as the central point for time and date calculations (the prime meridian), and the International Date Line sits at exactly 180° longitude from there.

By using Greenwich as the prime meridian, the International Date Line falls conveniently in the Pacific Ocean. In those few areas where it should traverse a landmass, the line was slightly bent to avoid dividing countries.

The date line is not governed by international law, and it is up to the individual countries to choose which side of the line they wish to be on. Occasionally a country decides to switch sides, as the islands of Samoa and Tokelau did last week.

To determine the Jewish view on the date line and Sabbath observance, we must examine four major opinions in halachah, Jewish law.

1. 90° East of Jerusalem

Rabbi Zerachiah ben Isaac Halevi Gerondi2 (12th century) and Rabbi Yehudah Halevi3 opined that the date line runs 90° east of Jerusalem.

The reasoning behind their opinion is that we consider Israel, and more specifically Jerusalem, to be the center of the “inhabited” world (at that time). In other words, six hours, or 90°, to the east and west of Jerusalem at one time encompassed the entire known world. The other side of the world (i.e. the western hemisphere) was considered the “lands of the sea.” Since the day begins to the east of Jerusalem, the quarter of the world to the west of Jerusalem, together with the entire western hemisphere, completes the day. Thus, the date line is 90°, a quarter of the globe, east of Jerusalem, or about 125° east of Greenwich.

The problem with this is that the date line would cut right through two huge landmasses—Asia (Russia, China, Korea) and Australia—and several Southeast Asian islands. You could end up with two people standing right next to each other, where for one the Sabbath is starting and for the other it is ending!4

As such, Rabbi Avraham Yeshayah Karelitz, known as the Chazon Ish, bases the 90° on the knowledge that the major landmass to the east of Jerusalem ends at that point. Since the entire landmass is on one side of the date line, the line actually zigzags, and so Siberia, Korea, eastern China, and Australia are considered to be on the west of the date line, while Japan and New Zealand are on the east side.5

According to the Chazon Ish’s date line, Sabbath in Japan and New Zealand is actually on Sunday.6

2. 180° East of Jerusalem

Rabbi Yechiel Michel Tucazinsky says that the date line runs 180° east of Jerusalem. He explains that because Jerusalem is considered the center of the land given to the Jewish people, it is also considered the center of the world according to Jewish law.7 Therefore, the date line would be located exactly 180° opposite Jerusalem, which would also enable every Jew in the world to observe at least 12 hours of the Sabbath together with those who live in Jerusalem.8

Since Jerusalem is 35° east of Greenwich, the date line would be 35° east of the current International Date Line, or 145° west of Greenwich. Accordingly, Hawaii and parts of Alaska would be on the western side of the date line, and the Sabbath in Hawaii would be on Friday.

However, it is possible that according to this opinion the line would zigzag around Alaska, in order that it follow the majority of the landmass.9

3. Mid-Pacific: Closely Resembling the International Date Line

Rabbi David Shapira opined that the date line is approximately 135°, or 9 hours, east of Jerusalem. This would make the date line approximately 170° east of Greenwich, which is only 10° off the International Date Line. According to R. Shapira, however, the line zigzags, slanting toward the Siberian coast as it goes through the Bering Straits, and then through the Pacific at 177°. Then it turns east of New Zealand.

His rationale for this placement is based on the statement of our sages that G‑d positioned the sun in the heavens at the end of the third hour of the fourth day of creation.10 Now, if it is the third hour of the day in Jerusalem, then three hours (45°) to the east of Jerusalem it would be noon, and nine hours (135°) east of Jerusalem the sun would be setting. To say that the sun was placed in the heavens on the fourth day, it must have been the fourth day on the entire planet. Therefore, we have to say that east of where the sun was setting, the fourth day was just beginning.11

Accordingly, Hawaii and Japan would observe the Sabbath on Saturday.

4. There is No Specific Date Line

According to Rabbi Menachem Kasher, since there is no clear tradition or Talmudic source, one should observe the Sabbath when the locals do. Since we, as individuals, are commanded to count six days and rest on the seventh12, when the first Jews settled in remote areas (over a long period of time), they simply continued counting six days and resting on the seventh. It was only later, when travel became more frequent, that the question of changing the dates arose.13

As such, there is no need for any community to change dates from their established custom (which is basically the same as following the International Date Line). However, travelers continue counting six days from the last Sabbath they observed, and the seventh day is the Sabbath. Only once the travelers arrive at their destination would they follow the local Jewish community’s Sabbath.14

The Samoa Issue

The Jewish Telegraphic Agency tracked down one Jew living in Samoa, and there may be many more. When would this person mark future Sabbaths?

It would depend on which of the above opinions he follows.

According to the first opinion—that the date line is 90° east of Jerusalem—then it runs west of Samoa, so until now the Sabbath was on Saturday. But now that Samoa has switched to the western side of the International Date Line, Sabbath would actually be on Sunday.

According to the second opinion—that the date line runs 180° east of Jerusalem—these islands, as well as Hawaii, were always west of the line. So until now the Sabbath in Samoa was actually on Friday, but now it will be on Saturday.

If, according to the third opinion, we say that the date line is 135° east of Jerusalem, then it runs to the west of Fiji. This means that until now the Sabbath in Samoa was on Saturday, but from now on it will be on Sunday.

According to the last opinion, Sabbath observance is based on an existing Jewish community. If a traveler or tourist were to arrive on an island with no Jewish community, the traveler would continue to keep the Sabbath according to his or her individual count, as if still on a boat.15

In Conclusion

While there are a number of opinions about the date line within Jewish law, the fact that a country decided to arbitrarily alter the date line has no bearing on the Sabbath, other than to mix up the names of the days. We still work for six days and rest on the seventh, the Sabbath.

It is important to note that this is but a brief overview, and while it seems that most of the communities in the questionable areas observe the Sabbath on Saturday, the laws are complex. One should consult a seasoned, knowledgeable rabbi before traveling.

See How Do We Know Which Day Is Shabbat? from our minisite on Shabbat.


Kuzari, 2:18–20.


Baal Hamaor, Rosh Hashanah 20b. We read in the Talmud there that a day may be declared Rosh Chodesh, first day of the new Jewish month, only if the new moon appeared in Israel by noon of that day—i.e., at least 6 hours before day’s end. R. Zerachiah explains that this ensures that at least somewhere in the world there will be a full 24-hour day of Rosh Chodesh. This means that the day begins 6 hours east of Jerusalem, and the area just to its east is 24 hours behind it, and 18 hours behind Jerusalem.


Kuzari cited in note 1.


Rabbi Yitzchak Yisraeli, Yesod Olam 2:17 and 4:7–8.


“Kuntres Shemoneh Esreh Shaot,” printed in Chazon Ish, end of Hilchot Shabbat.


It should be noted that there are a number of difficulties with this approach (some of which have been noted and discussed by the Chazon Ish himself). The line 90° east of Jerusalem does not actually coincide with the eastern edge of the landmass on which Israel is located, but is partially to the east of it, in the Pacific Ocean. Additionally, the problem is not just that the landmass is split in half, but that if we go strictly by the 90° line, the majority of Australia would be on the east side of the date line (i.e., the side on which the United States is located), and only a small part would be on the west side, the side of Jerusalem. This would have meant that the Jewish community in Australia (which already existed at the time this question arose, during World War II), which was used to keeping the Sabbath on Saturday, was keeping the wrong day, and should have been keeping the Sabbath on Sunday. Therefore, the Chazon Ish was forced to say that the majority of Australia which is to the east of the 90° line is “drawn after” the small part which is to the west, in order that they continue to observe the Sabbath on the day they were accustomed. But many point out that it is illogical to say that the majority of the land gets drawn after after a small portion; see comments by the Rebbe (Rabbi Menachem Mendel Schneerson, of righteous memory), Shaarei Halachah Uminhag, vol. 2, p. 153. Furthermore, the commentaries of Rabbeinu Chananel, Rashi, Tosafot and Rabbi Abraham ben David on the Talmud (Rosh Hashanah loc. cit.) explain the statement there differently; according to them it is not referring to the date line and has no bearing on it.


Midrash Tanchuma, Kedoshim 10; Talmud, Yoma 54b; Zohar 2:157a–b.


Sefer Hayomam B’Kadur Ha’aretz, ch. 23. This would appear to be the opinion of the Yesod Olam (cited in note 4) as well.


See Talmud, Eruvin 76a; Yesod Olam, ibid.; Shaarei Halacha Uminhag ibid.


Responsa of Rabbi Hai Gaon, Otzar Hageonim, Rosh Hashanah, p. 21; “Pirush” on Maimonides’ Mishneh Torah, Kiddush Hachodesh 9:3.


Responsa Bnei Tzion, vol. 1, 14:6, 13. It should be noted that there are other opinions similar, but not identical, to the one expressed by Rabbi Shapira. For example, Rabbi Binyamin Rabinowitz-Thumim, “Kuntres Gevul Yom” (published in the journal Hapardes, Iyar 5714 (1954)).
Others, however, note that there are actually six opinions as to where the luminaries were set on the fourth day. Additionally, according to this opinion we are saying that a place other than Jerusalem is the center of the world, something which we do not find referenced anywhere in the Talmud or Midrash. See Hayomam Bekadur Haaretz, ch. 22, and Kav Hataarich Hayisraeli, ch. 27 (see also Agan Hasahar, p. 474). In addition, according this opinion, that the line bends does not follow the majority opinions, including that of the Geonim, Rabbi Eliyahu of Vilna (known as the Gra), and Rabbi Schneur Zalman of Liadi in his prayerbook.


See responsa of Rabbi David ben Solomon ibn Zimra, the Radbaz, 1:76.


Kav Hataarich Hayisraeli. This is also the view of Rabbi Isser Zalman Meltzer, author of Even Ha’azel, in his approbation to this work, as well as Rabbi Tzvi Pesach Frank, Har Tzvi, Orach Chaim 138, based on the responsa of the Radbaz cited in the previous note.


This view is considered problematic. In numerous places in the Talmud we read while the sanctification of the moon, and the holidays that are dependent upon it, are dependent on the beth din (central Jewish court), the Sabbath is not, as it is already sanctified by G‑d. Additionally, it would come out that the day of the Sabbath in a given place can change, something that even R. Kasher agrees is problematic. See R. Tucazinsky’s rejoinder to R. Kasher in Talpiot, Nissan 5704 (1944). R' Kasher actually advocated establishing the International Dateline as the dateline in Jewish law, but only with the agreement of the central rabbinic court in Israel. Until that is done, his opinion remains unchanged.


R. Kasher addresses this very situation in “Shabbat Bereishit—Shabbat Sinai,” Talpiot, Tevet–Adar 5704 (1944).

Rabbi Yehuda Shurpin responds to questions for's Ask the Rabbi service.
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levi rapoport brooklyn May 17, 2016

Chabad's Opinion Interesting. The Shluchim in Hawaii and Japan both wrote to me that they keep Shabbos on the local Saturday. So Chabad doesn't follow either of the famous opinions regarding the dateline: The 90 degree line (Bal Hamoer/ Chazon Ish) OR the 180 degree line (Rav Tuchachinsky). I guess we follow Rabbi Dovid Shapiro who puts it close to the legal dateline, or Rav issur Zalman Meltzer who says there is no dateline) Reply

Yakov Kulik July 10, 2014

What is the psak din I think that you should consult a rav and put a psak din. The discussion is great but the person also and mainly wants to know bottom line when to keep Shabbos. Reply

Gregory Koch Storrs, CT February 24, 2012

Re: Alaska Along the same lines of the previous question, if the "local custom" in Alaska was to observe Shabbat on Saturday, and then Alaska made the Switch from Saturday to Friday, but decided to make it on a Saturday, such that it went Friday-Saturday-time change-Saturday-Sunday, (I have no idea what the day of the week was when they changed over, but they would have to repeat some day) should one have, for that week, lit Shabbat candles on Friday night, done Havdalah on Saturday night, then immediately lit Shabbat candles again since the next day was Saturday, before doing Havdalah again the following night? Or would you just "skip" that Shabbat and go 8 days between the two observances? Reply

Gregory Koch Storrs, CT February 24, 2012

Question Say we go with the "local custom" approach, and also suppose that I live in a Jewish community in Samoa which observes the Sabbath on Saturdays. Ordinarily, I would light the candles on Friday night and I would continue to do so after the time change. But for the week of the time change, where there is no Friday night, should I have lit them on Thursday night, since the next day would be Saturday? Reply

Feigele Boca Raton, Florida January 29, 2012

where ever you are there you are! Isn't Shabbat on Friday night and at sundown no matter where you are and no matter if you already had a Shabbat somewhere else because of traveling to a different country!
Why look for noon at 2pm (French saying) Reply

dale fancy gap, va January 28, 2012

many sabbaths Was not Shabbat sanctified when G-d stopped His work and rested or was it so man could rest up after six days? Did I read somewhere the Temple Mount is G-d's center of the earth / center of creation? I think the clock was made by man. Seems to me the Sabbath begins at say 6PM Jerusalem time. If you begin 6PM Honolulu time you have missed it by more than a few hours. How many Sabbaths are there? Reply

alfredo grabarz Sao Paulo, Brazil January 16, 2012

how many shabat hours do we have every week? Dear Rabbi
How many hours does the holiness of Shabbat rest upon earth each week? many hours does we have each week since the first hour of Shabbat starts at some place on earth till the last hour of Shabbat ends at any place of the earth? Reply

S. Meltzer New Haven, CT January 15, 2012

Re: A new need You are partially correct. The concept of the "circumnavigator paradox" was written by Abu'l Fida. However, it is reasonable to believe that the idea was discussed as a thought experiment before that. (Once the earth is spherical, as was known since ancient times, the issue is evident.) As I say, it was not largely relevant except hypothetically to a few philosophers, until someone could conceive of practical circumnavigation. At any rate, Yehuda HaLevi is the first known to find a practical application and write it down, because it was relevant to Jewish law. Reply

Rabbi Noson A Kopel Brooklyn, New York via January 15, 2012

Alaska The whole of Alaska had the same question (although it is uncertain if any Jews were there at the time) when changing from a territory of Russia to one of the United States. The Russian "Saturday" became the American "Friday" etc. Such things happen. But can the community (according to the opinion 4 above) then change their 'custom" if there was a prior one? Reply

Yehuda Shurpin (Author) January 15, 2012

Re: A new need Rabbi Yehuda Halevi, author of the Kuzari,is as far as I know the earliest work that we have which articulates the need for a dateline, Rabbi Yehuda Halevi lived from 1075–1141. as far as I know, the first recorded work in the Arab world which discusses the need for a dateline is in Abu'l-Fida's 'Taqwim al-Buldan' ('A Sketch of the Countries' or 'Geography'), Abu'l-Fida lived from 1273-1331. Reply

S Meltzer New Haven, CT January 15, 2012

A new need The idea that there were timezones was a new concept in the 1100's. Before that, it was irrelevant in that no one ever conceived of traveling that quickly or communicating across places where it might be day here and night there. The sources of the Kuzari came from the secular Arabic world, where astronomy was a developing study, as we see from his contemporary, the Rambam. Indeed the Rambam should have mentioned it if it were central to Halacha.

The strength of R. Kasher's answer is that it does not depend on timezones at all and would work even without known or consistent timezones. It is merely a count based on observations, achievable by a traveling layman, founded on a pedigreed halacha. Reply

derek kihei , hi January 13, 2012

dates I live on Maui . The tribe here are the last to light Shabbos candles. So then we also are known as being the last to say goodbye to Shabbos. Do we pray east or west ? Reply

RS minn January 12, 2012

@Mike Stutzer Try reading the artice again, specifically the second paragraph "The concept of a date line, and the fact that a traveler would either gain or lose a day after circumnavigating the globe, had been discussed in Jewish works hundreds of years before the establishment of the International Date Line."

It is apparent from this article that Halacha doesn't have limits at all. It conceived of the idea and discussed it long before any other scholarly work. Torah is limitless. It contains everything we need to know to live in this world.

Just because this article doesn't discuss the final Halachik ruling doesn't mean there isn't one, it means that it will depend on your Rabbi and your specific situation.
Even says it in the final paragraph; "It is important to note that this is but a brief overview...One should consult a seasoned, knowledgeable rabbi before traveling." Reply

izzy p January 11, 2012

Wow! Very impressive article! Keep up the amazing work Chabad! Reply

Mike Stutzer Boulder, CO January 11, 2012

international date line I am sure you tried to clarify the issue, but as is sometimes the case in Jewish Law, we see that Halacha has its limits. Reply

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