NOTE: Most of these time calculations assume the day is either the autumnal or vernal equinox, where there are 12 hours of sunlight and therefore Neitz is at 6:00 AM and Gra's shkiah is 6:00 PM

There is an extremely famous argument on when the start of halachik night (tzeis hakochavim) is. There are two main opinions:

  • THe opinion of Rabbeinu Tam, who states it is 72 minutes after sunset (what we consider sunset)
  • and the opinion of the Gr"a, Rabbi Eliyahu of Vilna, who states it is 13 minutes and 30 seconds after sunset.

Now, my question is like this:

It is obvious from the words of Rabbeinu Tam (Berachos Daf 2a Tosafos D"H Mai'aimasai) that they (i.e. the people during the times of the Rishonim) recited Krias Shema after Plag Hamincha. This means they prayed at some point after 75 minutes before Rabbeinu Tam's tzeis [1], meaning that the prayed sometime after 5:57 PM.

Now, Rash"i says (Berachos Daf 2a D"H Ad Sof) that the people prayed before tzeis. This fits with both shitos (i.e. Rabbeinu Tam and Gr"a), because if he held like the Gr"a they davened sometime before 6:13 and a half, and if he held like Rabbeinu Tam they davened sometime before 7:12. This fits with what we said earlier that they for sure davened after 5:57.

Now, the R"i (Berachos Daf 2a Tosafos D"H Mai'aimasai) states that they prayed after the start of Bein HaShmashos [2] and before Tzeis. This cannot fit with both the Gr"a (for whom the time period would be 6:00 - 6:13:30) and Rabbeinu Tam (for whom it would be 6:58:30 - 7:12).

Now, we cannot prove whom Rashi held like, however we can assume that the R"i held like his Rebbi Rabbeinu Tam, and thus thought that Bein HaShmashos started at 6:58:30. Therefore, the people davened after 6:58, and yet Rashi still states that it is before Tzeis Hakokhavim, therefore seeming to be a proof that Rashi holds like Rabbeinu Tam and not like the Gr"a.

However, it is not a complete proof because it could be that R"i disagrees with Rabbeinu Tam.

Thus, my question is as follows:

Do either Rash"i or R"i either hold like Rabbeinu Tam?

Either way, please back up your answer with sources...

1 It could be that they prayed even earlier if we assume that a sha'ah zemania is calculated from alos until tzeis, but for the purposes of simplicity I will assume from neitz till shekia.

2 He says that they said Shema acc to R' Eliezer in the Braisa on Berachos 2b, who says from Bein HaShmashos

  • He was before them so the question is backwards. You mean to ask if the gra or rabenu tam held like rashi
    – Dude
    Commented Sep 27, 2023 at 9:12
  • 1
    The likeliest possibility would seem to be like neither of the two opinions you quoted. It seems common practice in Europe for centuries was to assume tzeit hakochavim was when they could see three stars, and then bein hashemashot started 15-20 minutes before that (well after observed sunset (our "shekia") but much less than an hour after it). See for example ShuT Chasam Sofer OC 80, who assumes he is following RT and writes that tzeit hakochavim at the end of Sivan was 8.55 - around 50 minutes after our shekia at that time of year.
    – Joel K
    Commented Sep 27, 2023 at 9:37
  • 1
    @Dude Granted, but the opinions in the vernacular are referred to as "Gr'a" and "Rabbeinu Tam", so I kept those names...
    – fartgeek
    Commented Sep 27, 2023 at 11:22
  • @JoelK good point...
    – fartgeek
    Commented Sep 27, 2023 at 11:23

1 Answer 1


This is not an issue just of the Gra. The time of the Gra and the Alter Rebbe is called zman haGeonim because is based on the shitta of the Middle East Geonim.

Rabbeinu Tam is based in the great gaon of the West, Rabbeinu Gershom, Ohr HaGola.

Some like Maharam Alshaker 96 marshals the Rashi Shabbat 35a s.v. karmel as a proof that Rashi disagreed with Rabbeinu Tam. See Rashba Shabbat 35a and Ramban Torat Adam who endeavor to make the gemara fit with Rabbenu Tam but in doing so reject Rashi, though not necessarily because they thought he disagreed with Rabbenu Tam.

  • Where does the Gra base his opinion on Middle Eastern Geonim? Where does Rabbenu Tam base his opinion in Rabbenu Gershom?
    – Double AA
    Commented Sep 27, 2023 at 11:24

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