why is tu bshvat 1 day?
It's from the Torah(so in that sense, it's in the same bag as pesach shavuot and succot). (it's sourced from sheb'al peh - but that shouldn't make a a difference)

It has no ritual, so there's no risk of doing a ritual on the wrong day. But surely that doesn't justify it being kept on the wrong day! so doesn't matter if you keep it on the wrong day. Hence only 1 day?!
Furthermore, by that reasoning, we could move tu b'shvat to any old day . Likewise for any festival with no ritual.
Also, To those that day that TuB'shvat has no ritual therefore it's 1 day, they should consdier chanukah and purim, which do have ritual, and are also 1 day.

Why is purim 1 day?
chanukah and purim. rabbinically ordained, so the crazy explanation i can think of for why we don't do extra days for those festivals, is that the rabbis consider it ok if we get the day wrong. This is not an explanation! So, people have a problem if they say that chanukah and purim don't have extra days because they're nto from the Torah. Those festivals have rituals, so surely it's 'especially important' to get it on the right day.

have i asked this q badly?!

Welcome to the Global Yeshiva. You asked very well.

From the following sources we can see that our main concern about not knowing the correct day of Yom Tov is because we may come to be over an issur (negative commandment). So it appears that if there is nothing forbidden to worry about, there is no need to keep two days.

Rashi explains on the following Gemara in Betza that a bad decree we may prevent us to learn Torah and we could forgot how to calculate the months. We would then not have the correct day of Yom tov and come to eat chamutz on Pesach.

Gemara Betza 4b states:
R. Zera said: Logic supports R. Assi; for we are now well acquainted with the fixing of the new moon and, nevertheless, we do observe two days. Abaye said: Logic supports Rab; for we have learnt: In early times they used to light bonfires, but on account of the mischief of the Samaritans the Rabbis ordained that messengers should go forth. Now if the mischief of the Samaritans ceased we would all observe only one day; and even during the Samaritan mischief wherever the messengers arrived they observed only one day. But now that we are well acquainted with the fixing of the new moon,why do we observe two days? — Because they sent word from there (Palestine): Give heed to the customs of your ancestors which have come down to you; for it might happen that the government might issue a decree and it will cause confusion.

The Shulchan Aruch 496-1
In the Diaspora, where two days of Yom Tov are observed in view of the doubt regarding the actual day on which Yom Tov falls, whatever is prohibited to be done on the first of these days is also prohibited to be done on the second. The Sages would ban someone who treated the second day lightly. If the offender was a Rabbinical student they were not so stringent as to ban him, but they would flog him for rebellion.

Mishnah Berurah 496-1
Although we are now familiar with the determination of the new month, which today follows prescribed calculations that we have been taught, the Sages were nevertheless concerned about this matter. They were afraid that through the many sufferings and transportations of our Diaspora the correct calculation may be forgotten and people will come to make a month which should lack a day a full month or a month which should be full lacking a day and would thus come to eat chametz on Pesach. Consequently, they left the ruling in this respect outside the land of Israel as it was in the early days , when people did not know when the new month was determined.

thanks, that answers msot of my prob, curing my confusion over rabbinically ordained festivals and whether there are rituals.

But I can still see a few oddities

Holy days where there's prohibition and the festival is 1 day. And a case where there's no prohibition and it's 2 days.

* Fast days are 1 day (yet there's a prohibition against eating)

* 7th day of Succot = Hoshana Rabba. No prohibitions, but it's 2 days. Thus succot's '8th day' extends to the 22 Tishri

quote:

Originally posted by davidt:
thanks, that answers msot of my prob, curing my confusion over rabbinically ordained festivals and whether there are rituals.

But I can still see a few oddities

Holy days where there's prohibition and the festival is 1 day. And a case where there's no prohibition and it's 2 days.

* Fast days are 1 day (yet there's a prohibition against eating)

* 7th day of Succot = Hoshana Rabba. No prohibitions, but it's 2 days. Thus succot's '8th day' extends to the 22 Tishri

As to fast days (and we are really only talking about Yom Kippur) I believe it is the case that our Sages realised that it would be too difficult to expect people to fast 2 days in a row.

As to Hoshana Rabba, that seems to be an exception as there are no extra prohibitions over and above those of Chol HaMoed (the intermediate days of the Festival). But we don't actually do anything on the 8th day (Shemini Atzeres and also 2nd day Hoshana Rabba) that would contradict the observances of Shemini Atzeres. So we don't shake the Lulav nor do we make a Bracha when we sit in the Succah.

Not just Yom Kippor
Yom Kippor is one. Tisha B'Av is another.
I can speculate that it is probably because 2 days is too difficult too. Though it'd be interesting to see a source. Remember in other places (not this site) I have seen lots of wrong statements from people that thought that tu b'shvat was 1 day because it had no ritual!! Or was not in the written Torah. That was really speculation and was incorrect reasoning.
Perhaps there is a worst case scenario where the rabbis say 'fast -1 day - even if you got the day wrong - it's ok' Or perhaps there is also some other reason, like in the case of yom kippor, perhaps 10 days into the month was enough. I wonder how far out from the jerusalem court is deemed 'diaspora'. But that is really just asking more questions.

You say Hoshana Rabba is the odd one out. How do you know? You said 'it seems'. That is speculation. Maybe there is an extension to the rule that the festival should jus have 'no prohibitions'. Perhaps it being so late in the month, messengers would have reached the 'far out' communities. Goes back to how far out is far out to be considered equivalent to the diaspora today - how many days away for messengers to travel (perhaps less than 21 days = HR being the 21st).
I do think that Hoshana Rabba is not an odd one out. And fits perfectly in. It's only the odd one out if you didn't consider the extension to the rule. It is only the odd one out to one that is unclear as to why some festivals are 2 days in the diaspora. Thus, it wrould be absolutely wrong to think of it as an odd one out

quote:

Originally posted by davidt:
Not just Yom Kippor
Yom Kippor is one. Tisha B'Av is another.
I can speculate that it is probably because 2 days is too difficult too. Though it'd be interesting to see a source. Remember in other places (not this site) I have seen lots of wrong statements from people that thought that tu b'shvat was 1 day because it had no ritual!! Or was not in the written Torah. That was really speculation and was incorrect reasoning.
Perhaps there is a worst case scenario where the rabbis say 'fast -1 day - even if you got the day wrong - it's ok' Or perhaps there is also some other reason, like in the case of yom kippor, perhaps 10 days into the month was enough. I wonder how far out from the jerusalem court is deemed 'diaspora'. But that is really just asking more questions.

You say Hoshana Rabba is the odd one out. How do you know? You said 'it seems'. That is speculation. Maybe there is an extension to the rule that the festival should jus have 'no prohibitions'. Perhaps it being so late in the month, messengers would have reached the 'far out' communities. Goes back to how far out is far out to be considered equivalent to the diaspora today - how many days away for messengers to travel (perhaps less than 21 days = HR being the 21st).
I do think that Hoshana Rabba is not an odd one out. And fits perfectly in. It's only the odd one out if you didn't consider the extension to the rule. It is only the odd one out to one that is unclear as to why some festivals are 2 days in the diaspora. Thus, it wrould be absolutely wrong to think of it as an odd one out

As Rabbi Mitterhoff said, the reason for the 2 days is that our Sages were concerned that a Torah prohibition might be transgressed. So Tisha Be'Av, which is purely Rabbinical, need only be one day.

Hoshana Rabba is an exception as there are no prohibitions of the day itself.

As to Yom Kippur, one should bear in mind that the second day of any Yom Tov is Rabbinical in nature only. The Rabbis would never decree anything that they felt the Jews wouldn't abide by, and this possibly applies to a second day Yom Kippur.

some news

recap. Succot is 8 days in Israel. 9 days in the diaspora.

I erred. HR is not 2 days.
Hoshana Rabba - the last intermediate day of succot, Chol Hamoed, is only 1 day long.

I erred again.
The whole Tu B'shvat 'festival' is a custom. Made more popular since modern zionism.

It appears to me that all biblical festivals seem to have probitions on the last day.

All biblical festivals are extra days.
(it'd be interesting to nkow if there are any biblical festivals with no probitions on any day or no probitions on the last day?)

As I have explained, HR is indeed 2 days, but as it spills over into Shemini Atzeres we don't observe all the customs of HR (shaking Lulav, taking the Arava). We do, however, still eat our meals in the Succah (there are different customs about this) but we do not recite the Blessing.

the 22 Tishri is Both Succot and Shmini Atzeret. It is the last (8th) 'biblical day' of succot.

We agree on the special reason why the lulav is not shaken on the 22 Tishri.

The command is to shake the lulav on succot. HR is just a day of succot. It's the 21st Tishri, and it's chol hamoed. We shake the lulav, not as a HR custom. but as a Succot Law.

Thus, your reason for saying HR is 2 days, is faulty.

I'm hoping somebody can come up with a source to settle the issue! To show whether HR is 1 day or 2.

I say 1 day !!

The Gemarah in Sukah from 46b-47a deals with the question Shmini Safek Shvi (the 8th day that is Safek being the 7th day) do we sit in the sukah and do we make a Bracha. The Maskanah of the Gemarah is Meisav Yasvinan Bruchai Lo Mivarchina (We sit in the Sukah but we don’t make a Bracha.) Tosfos (DH Meisav) says we didn’t want to enact to take the Lulav on Shmini because it’s Mukzah (on a regular Shmini) thus taking it now would be obviously showing that it’s a weekday and not Yom Tov (so it’s disrespectful fro Yom Tov to do that.) Sukah on the other hand doesn’t show it’s weekday (even though on a regular Shmini you wouldn’t sit there) because sometimes someone would picnic in his Sukah because he likes the fresh air, so it’s not so obvious he’s sitting there because it’s Sufaik Sukos.

The bottom line, it seems that they would of made it a second day, if it wasn’t Yom Tov and doing Sukkos thing on it is a B’zayon (degrading) for the yom Tov, thus only things that are not obviously Sukos activities are permitted and thus obligated.

I‘m not sure the relevence if it’s a Sukkos or HR, since they’re practically the same Halachically, (which is only difference is the Aravah which is only a Minhag Naviyim (so that’s the reason we don’t make a Bracha on it.)) And the Arava you wouldn’t take on Shmini for the same reason as Lulav.