When does Shabbat fall in the Pacific Ocean?

Take Apia, the capital of Samoa, for example. This Friday, sunset will be at 6:10 p.m. Subtract 18 minutes, and you have Shabbat beginning at 5:52 p.m. on Friday evening.

Which, because Samoa is 17 hours ahead of Eastern Daylight Time, already has happened if you’re reading the Jewish Standard on Friday evening.

But not so fast.

Up until December 2011, Samoa was on the other side of the International Date Line. In those days, Samoa was seven hours behind us. That means that Shabbat would be yet to begin when we light candles here in New Jersey.

To make the shift, Samoa skipped a Friday and jumped straight from Thursday to Saturday.

Would Shabbat have followed along? Or would it continue to be seven days after the previous Shabbat? That would mean that Shabbat would fall on Sundays in Samoa, at least until the International Date Line changed again.

That wasn’t a pressing question when Samoans debated the move: Apia’s community of observant Jews is as non-existent as you might expect. However, the island nation does have real communities of Seventh Day Adventists, some of whom (but not all) now observe their Sabbath on Sunday. After all, how can a vote by the people of Samoa change the day of the Lord’s Sabbath? Yet is the new date of Samoa any less arbitrary than the International Date Line, which first was drawn in 1884? And yet again, how can you not have a line somewhere dividing one day from the next?

The notion of a date line in Jewish law was raised by the 12th century. The assumption was that the line was far enough east of Jerusalem to serve as a thought experiment, not a real-life challenge. At least half of the globe, it then was assumed, was ocean, so wherever that line fell was, it was so far to the east of Jerusalem (and farther to the east of the medieval rabbis discussing this in Europe) that it didn’t really matter.

As the world was explored and mapped, it became clear that what had been an abstract line in the 12th century passed near Shanghai — part of the real world. That put Japan on the other side. So did Jewish law consider Japan, which according to the international system of time zones had the same date as China, as actually being a day earlier? This became a problem about 100 years ago, as some Orthodox Jews found refuge from the first World War in Japan. It became a more serious question in 1941, when hundreds of yeshiva students from Lithuania made their way to Japan.

Should the refugees in Japan observe two days of Shabbat just to be safe? Should they fast for two days on Yom Kippur?

So they telegraphed to Jerusalem to get guidance. But not all the telegrams were sent to the same rabbi, and the return cables contained a plethora of conflicting answers. In the end, a meeting was convened in the chief rabbi’s house in Israel to try — unsuccessfully — to reach a conclusion.

“It’s a very complicated topic,” Shlomo Korsinsky said. “There are a lot of different opinions.”

Shlomo is one of the area’s leading experts on this abstruse question of Jewish law. A student at the Torah Academy of Bergen County, the Englewood 17-year-old was co-captain of the school’s team, which debated the topic of the international date line in Jewish law at Touro College’s recent fourth annual Model Beis Din competition.

The team won.

Shlomo and his teammates debated two other teams, and then fielded direct questions from Touro rabbis.

The tournament organizers had sent the students the topic and two of the most prominent halachic opinions on it a few weeks before the contest. Rabbi Avrohom Karelitz said that while all of the Asian landmass fell on the same side of the dateline, Japan was offshore, to the east of the dateline, and that therefore the yeshiva students should observe Shabbat on Sunday.

Rabbi Yechiel Michel Tukitchinsky, however, put the halachic date line further east — keeping Japan’s Shabbat on its Saturday, though perhaps causing problems in Alaska.

(The notion of actually abiding by the international date line was suggested by Rabbi Menachem Kasher, but the commonsensical approach was widely rejected by his Orthodox colleagues, even though it probably reflects the practice of most Jews. If nothing else, it makes rather thin gruel for academic debates.)

The key to TABC’s victory — the team has won every one of the four annual contests to date — was not limiting themselves to the assigned sources.

“To win you have to know far beyond what you’re expected to know,” Rabbi Howard Jachter said. Rabbi Jachter teaches at TABC and has written four books about Jewish law. He is the team’s coach.

“We prepare the guys for questions far beyond the basic material,” he said. “Plus we have students who have a very strong knowledge base to begin with.”

The TABC team won all of the previous competitions as well.

“There are 13 opinions on the topic, according to the Enyclopedia Talmudit,” Rabbi Jachter said. “We mastered all of them, and many, many other topics related to the international date line.”

“Obviously, it’s a very good thing to win,” Shlomo said. “But the most important thing by far was the opportunity to learn the subject very well.”

Did he have a favorite among the rulings he studied?

“All of them are holy,” he said. “I’m not big enough to decide. Each one is correct in their own way.”

Did the experience make him more or less eager to go to Japan?

“Less,” he said, pointing to the uncertainty of when Shabbat would occur. “I see the gravity of how serious the question is.”