Laws of Sanctification of the New Month, Chapter 8 (Auto Translated)

Chapter 8 of the Laws of Sanctification of the New Month — Calculation of Full and Deficient Months

Introduction: The Order of the Chapters

Good day, dear Jews. Today we are going to finish learning how to make a calendar. We are going to learn Chapter 8 of the Laws of Sanctification of the New Month, and we thank the donors who pay for the calendar and for the Rambam and all other things, and we will learn this way.

That is, we have already learned how we know when the molad (new moon) is, Chapter 6. We have already learned when Rosh Hashanah is, that it’s not only according to the molad, but according to all the rules called the dechiyot (postponements), Chapter 7. Yes. Now one needs to know, according to this one will have to calculate the rest of the months. But one needs to know when each month is Rosh Chodesh (the new month). Ah, good. Now, for this one needs to know the rule.

That is, if you want to know the molad of each month, the molad hametzuyah that is announced on Shabbat Mevorchim, aside from this there is no other practical difference, one calculates 29 days, 12 hours, 793 chalakim (parts) from Rosh Hashanah. But the Roshei Chadashim (new months) are not calculated with this. Rosh Chodesh has a different order, and this we will now learn. Right? It is also calculated with this, but there are still issues that need to be settled. No, it’s not calculated with this at all. They are calculated with this because it’s a fact. If one cannot calculate only with this because of certain problems, one doesn’t calculate with this at all.

If you want to know, that is, the rules are built on this, but if you want to know when Rosh Chodesh Tammuz will be in the year 5786, that won’t help you at all. You need to know what’s written in this chapter. What’s written in this chapter is certainly built on how long the lunar month truly is, that is the averages, and according to this he makes rules, but we will go with the rules.

Laws 1-2: The Lunar Month — You Calculate Days for the Month

The Rambam’s Words

The Rambam says this: The lunar month, the month of the moon, that is to say how long it lasts from when the moon is born until it is born the next time, is twenty-nine days, and a half, and chalakim. In your text it says “and chalakim.” In your text it says “and chalakim.” It’s 793 chalakim. Not 793, it is 793. But… Reb Moshe Wiener… No, it’s better to say it this way than to say it without the number, because it’s already seen. Okay. The Rambam says this in the next law.

So it means, there is a problem here if it’s 29 and a half days, meaning, let’s say we would have said Rosh Chodesh is the thirtieth day, but Rosh Chodesh should already be half a day before that. But how is it possible to say that Rosh Chodesh should be in the middle of the day, that the half, when the previous month has ended, then Rosh Chodesh should begin? So that it would come out that half the day would be from the previous month, and half from the coming one, in the middle of the day, after noon, then the new month begins. This cannot happen.

The Learning: Halachah LeMoshe MiSinai (Law Given to Moses at Sinai)

Why? For this there is a halachic reason why it cannot happen, as it says “ad chodesh yamim” — a month of days. So we see that in the month there are only days. From the oral tradition they learned, the Sages have a halachah leMoshe miSinai, that yamim atah mochashev lachodesh, only a certain number of days together make a month, but i atah mochashev sha’ot, it cannot be that it should be days plus hours that make a month.

Discussion: Why Do We Need a Halachah LeMoshe MiSinai? It’s Simple Common Sense

This is seemingly simple. It’s very interesting, because this piece “yamim atah mochashev lachodesh” appears in Rosh Hashanah, it’s not clear, Rashi has a different interpretation of what it means. But the Rambam learned that the Gemara means to say that when one makes the month according to calculation… It’s not when one makes it according to sighting, when one makes it according to sighting, when one sees the moon, then that whole day, that day, you begin the start of the month. But when one makes it according to calculation, we know precisely, we have a precise calculation, 29 days, 12 hours, 793 chalakim, one could have thought to make Rosh Chodesh then.

To this the Rambam says, one needs a teaching, a midrash. I mean one doesn’t need any teaching, it’s simple. It’s difficult for a day, one needs to know in the morning for the children to put on white shirts. What will he tell you? Will you put on from three o’clock in the afternoon you’ll put on a white shirt? There are laws of Rosh Chodesh, one needs to bring the sacrifice. It’s very funny. And this is faith, one needs to derive from a verse, one needs to derive from the oral tradition. We see it as simple logic.

The Rambam’s Approach: Halachah LeMoshe MiSinai vs. Derived from the Verse

It’s also interesting that he says “ad chodesh yamim,” he says it’s a halachah leMoshe miSinai. He will have a very similar law about how you calculate years, but there it’s not a halachah leMoshe miSinai. It says “lechodshei hashanah,” simply derived from the verse. Interesting, here it wasn’t enough for him simply that it’s nice, one can derive it from the verse without a halachah leMoshe miSinai.

No, no, because every Rambam, remember, let’s review for the thousandth time what the Rambam holds, all the laws of the commandments are halachah leMoshe miSinai. Some of them also appear in the verse, and that’s fine, it also appears in the verse, it doesn’t hurt to have it a bit in the verse. Some appear only in the verse if one believes the halachah leMoshe miSinai. In other words, from the oral tradition. He says that this is the meaning of the verse. You could learn a different interpretation in the verse, but nevertheless, the real reason we follow it is because of the tradition, not because of the verse. If something that we follow only because it’s written in a verse, it would be rabbinic, from the words of the Scribes. These are the rules of interpreting verses which is not relevant here.

Innovation: The Half Day Does Have Significance

In any case, one doesn’t make any half days in any way. I do want to say something. Soon we will see that the Rambam seemingly says that there is indeed some significance that the sanctity of Rosh Chodesh has with the half day. It may be that it does make a practical difference, because in practice then is the molad and we know. It means, formally one never makes Rosh Chodesh in the middle of the day, but it may be that the half day causes it to be Rosh Chodesh. The halachah leMoshe miSinai doesn’t say that the day cannot be Rosh Chodesh. Rosh Chodesh just cannot begin in the middle of the day. So the real, when the molad is truly, it seems it is indeed real.

Question: Molad vs. Sighting — What Does the Calculation Count?

It’s terribly interesting, because one needs to ask a good question here, which I’ve already asked before, perhaps hinted at in the previous chapter. When one makes it according to sighting, when does Rosh Chodesh occur? When one sees the new moon, right? The molad is by definition before the sighting. And here something appears that although there are different rules, and one doesn’t do it precisely, but essentially it appears very clearly in the previous chapter, that today when one makes it according to calculation, one makes the new Rosh Chodesh at the molad, at the conjunction, at the molad, not at the sighting. It’s very interesting.

What’s the matter? Do you understand what I’m saying? The calculation counts something different than what the sighting counted. But by the sighting Rosh Chodesh also became from the molad. From the sighting? From the beginning of the day, no difference. When Rosh Chodesh is declared he will perhaps come later. Yes, I’m asking you a different question. All along we learn that the molad makes Rosh Chodesh. Why should the molad make Rosh Chodesh? The sighting should make Rosh Chodesh. And the sighting is by definition after the molad. But the sighting is not that when the molad occurred it was proven through a person seeing it. No, they’re two different things, it’s not proven. It’s afterwards, one cannot see the molad. At the molad one by definition cannot see the moon, it’s not possible, it’s completely hidden.

Okay, anyway, this is just a question, one needs to understand if there is an answer to this question or not. Now, according to what you say, the sighting always said that the molad has already finished, not that it’s now the molad, but the opposite. But we make, it doesn’t go like that, Rosh Chodesh falls when one sees. I mean, there isn’t… When Rosh Chodesh, let’s not say that the month goes with the moon. One could have also included Rosh Chodesh from the middle of the month until the middle of the month. It’s just a question, from where do you count? What’s the difference? But why the molad should be suddenly when one switched from sighting to calculation, it becomes a different thing, that the calculation doesn’t count the same thing that the sighting counted? Perhaps this is the meaning of “chodesh bechodsho”? I can’t say, I mean, why? No, the Sages had such a rule of “chodesh bechodsho.” Okay.

Laws 2-3: Deficient Month and Full Month — The Chalakim Accumulate

The Rambam’s Words

So, says the Rambam, since it’s impossible to make half a day, and it’s always 29 and a half days, one needs to compromise here. What does one do? Therefore we make the lunar months, some of them a deficient month of 29 days only, even though the renewal of the moon is more than this in hours. Even though the true month has another half day, we nevertheless make it a deficient month.

The Meaning of “Deficient” and “Full”

It’s very interesting, because now I understand the word “deficient,” not simply that it has only one month, but a deficient month. It means because we cut off half of it. Half a day from Adar we said, “No, it’s already Nissan.”

And a full month of thirty days, even though the renewal of the moon is less than this in hours. Here we added half a day, so as not to calculate hours in the month but only complete days. So, sometimes we borrow and sometimes we pay back.

If It Were Simply 29½ Days

Now, let’s think, if so, if it were simple, says the Rambam in law 3, if it were as I just said, it would continue to be good. One would always make one this way and one that way. If the renewal of the moon were 29 and a half only, without any chalakim, all the months would be a full month and a deficient month, and the lunar year would every year be one this way and one that way, it would run in an order of six and six. The lunar year would be three hundred and fifty-four, it would be six deficient months and six full ones. It would be three hundred and fifty-four days in the year, I mean 354, and it would be very good.

But the Chalakim Accumulate

But each month, besides the half, there are also chalakim, a fraction of an hour. Those chalakim that are in each and every month beyond half the day, how many chalakim, the nine hundred, I mean, yes? Seven hundred and ninety-three chalakim, will accumulate from them hours and days. So with time, penny by penny accumulates, from the chalakim become hours, and from the hours become days, until in some years the deficient months will be more than the full ones. It must come out that it should be that not all six should not be evenly six and six, but it should happen somewhere that deficient months are more than the full ones, and in some years full ones more than the deficient ones.

Should I explain? Until means that naturally one makes a pattern. Ah, one must make that sometimes it should be this way and that way.

The Mathematics of the Chalakim

How much would accumulate from the chalakim? So if one does the math, it comes out approximately… If you do a calculation, each month adds seven hundred and ninety-three chalakim, yes? So after twelve months you have nine and a half thousand chalakim, which is how many hours it is. It’s approximately eight hours and something. But if so after a year you still have only eight hours left over, not a big deal. Okay, so over three years it’s a day. Over two years is already, better, a bit more than two years, is already, what’s it called? Do you already have almost a whole day? Seventeen hours in two years. So two and a half years approximately is a whole day, you’ll be left over with a day. Therefore one must make years differently. Each year, there are certain years where one must add.

Day Thirty — Rosh Chodesh in the Calculation, and the Order of Full and Deficient Months

Law 4: Day Thirty We Always Make Rosh Chodesh

Right? Make once more than deficient, or once… Sometimes afterwards back to deficient, because it hasn’t yet come to go a whole day.

Rambam, if one has already paid too much, one can only count a whole day. If you need to pay back for the next year. This is basically the side, one borrows and one pays back. Like all these things.

Says the Rambam thus, day thirty, the thirtieth day of the month, we always make it Rosh Chodesh in this calculation, one always makes Rosh Chodesh with this system.

So what? If the previous month was deficient, if the month before it was deficient, then day thirty will be Rosh Chodesh of the coming month. Why? And the previous month was full. If there’s a deficient it’s nothing, then the next day is Rosh Chodesh, it’s the first of the next month, and good day.

If the previous month was full. It was thirty days, day thirty will be Rosh Chodesh, it’s still, the thirtieth day we already call Rosh Chodesh. Why? Hey, it’s full, it’s still part of the old month. Why? But it goes, when a bit of Rosh Chodesh, half a day is already yes the new month.

Essentially, it means, by law, you can’t call us, but it’s a new month, it means with the moon, we make that day Rosh Chodesh, but we don’t yet call it as the first of the new month, because perhaps this is part of the “and you calculate days for months,” he adds a few hours to the new month.

So it’s actually called Rosh Chodesh, but it’s still different than… It’s not the fulfillment, it’s not the definition of the word. Rosh Chodesh means the first day of the new month. So, it’s not… One cannot call it Rosh Chodesh from the aspect that it’s the first day of the new month, but we call it Rosh Chodesh, and it’s still the completion of the previous month that passed.

And the next day, day thirty-one, is already truly Rosh Chodesh, because it’s already the new month, “and from it is the counting and it is the day of establishment”. It’s not truly Rosh Chodesh, but it has the laws of Rosh Chodesh.

Explanation: Two Types of Rosh Chodesh — For Sanctity and For Calculation

Let’s explain a bit more clearly what’s going on here.

There are, people are terribly confused. People perhaps don’t know. People know that outside the Land of Israel there are two days of Yom Tov, and people also know that every other month there are two days of Rosh Chodesh.

A person might think, perhaps this is what many young men think, that it’s also a doubt about the day. It’s a doubt whether Rosh Chodesh is the thirtieth day or the thirty-first day, so one makes two days.

But this is nonsense. First of all, two days of Rosh Chodesh one makes also in the Land of Israel, it has nothing to do with any doubt. It’s not a doubt at all. Second, one makes it only every other month, one doesn’t make it every month. What kind of doubt is there? We know very well, we go according to the calculation.

But Yom Tov we say, we once didn’t know, therefore one makes two days as they learned. But then there actually was, this must be clear, there was once a thing of two days Rosh Chodesh. Once by sighting there was a doubt about the day, and afterwards there is no longer a doubt about the day, the opposite of the doubt about the day that we know. Not the opposite, the same.

There once was, and it wasn’t relevant to anything, only the Temple, the sacrifices. There once was a thing of doubt, one had to make, they observed that day as holy and the next day as holy. But nowadays there is no doubt, because one goes according to a calculation. It’s not relevant, there’s no such thing as doubt, there is a law that one goes according to a calculation.

Hey, why today do we make two days of Yom Tov? Because we remember from the times when we didn’t go according to a calculation, whatever. But regarding Rosh Chodesh there isn’t the law that one must remember. So regarding Rosh Chodesh there is no doubt about the day, it’s not a doubt.

Rather what, why does one make two days of Rosh Chodesh? The answer is, this is a completely different thing. Seemingly, if once it would have also been, even if one makes according to the calculation, or perhaps even when one made according to the sighting, for other reasons, but one makes two days of Rosh Chodesh. There are two days of Rosh Chodesh.

Why two days of Rosh Chodesh? The reason is this, because Rosh Chodesh is composed of two different things.

Rosh Chodesh has one thing, that now comes the new moon. The new moon comes, one must make Rosh Chodesh. Why? I don’t know, what is sanctity.

The second thing is that there is a calculation, one must count twelve months in a year, it should come out the calculation should be correct.

So, regarding the first thing, day thirty there is always a moon, according to the calculation. Again, even this isn’t true, but according to the calculation that we count, the molad hametzuyah, always on the thirtieth, therefore it’s always Rosh Chodesh, the sanctity of Rosh Chodesh is there.

The calculation that we need, we have here a reason why we cannot always make the thirtieth day Rosh Chodesh, because it’s missing, we would owe a day. Regarding this it’s not today Rosh Chodesh.

So you can call it the first day is Rosh Chodesh l’kedusha v’lo l’cheshbon, and the second is l’cheshbon v’lo l’kedusha, because there is no new moon on the 31st day. The moon was already there yesterday.

So it turns out on the second there is Rosh Chodesh for two different types of reasons: the first is because there is a moon, the second is because there is the calculation.

So says the Rambam. It’s true there’s a question, other Rishonim have spoken about this, they say other explanations perhaps, but this is the Rambam’s explanation.

Note: What does “l’kedusha” mean?

L’kedusha means that there is a chidush halevana, not regarding Rosh Chodesh. When one conducts the laws of Rosh Chodesh, what does it mean that one makes Rosh Chodesh? It can be a practical difference also regarding vows, the language of people, that it’s already called the next month.

There is in the days of the Gemara, one must understand halachically, it means that one makes a vow or a document for the next month, it can be that the first day Rosh Chodesh is already called, it depends on how people call it.

In any case, kedusha means to say that one observes Rosh Chodesh means to say one conducts malachti alav yavo and the like. One says according to our custom. In any case.

Proof from Sefer Shmuel — “On the second day of the month”

Therefore, since one must have that the half days should combine with the half days, one makes in this calculation, one month has only one day, one month has Rosh Chodesh for two days, meaning, and one sees bringing all, one already sees in the verse in Sefer Shmuel it says in the haftarah of Machar Chodesh it says “on the second day of the month”.

It’s implied that the custom of making two days Rosh Chodesh was an old custom, King Shaul already made two days Rosh Chodesh. It has nothing to do with doubt, I’m telling you. Perhaps then there was indeed a doubt, because they had it based on sighting, but the verse doesn’t look that way. It looks like there are two days that can be Rosh Chodesh.

It’s interesting, yes, because the moon they made regarding “the two great luminaries”, “that they should not use one crown”. Here one makes two days have the crown of Rosh Chodesh. Okay.

Halacha 5: The Order of Full and Deficient Months

“The order of full and deficient months according to this calculation is as follows”. When is this? When does one make it deficient and when full?

In other words, back to the fundamental way, one makes one deficient and one full, correct. The problem is, there remain the 1079 chalakim, so sometimes one must switch it. So the rule is as follows, what switches and what remains?

It’s like this, Tishrei is always full. Always full. It has an explanation based on the previous… It goes in an order.

The point is basically like this: essentially it goes in an order. It should have gone, the normal thing would have been Tishrei full, Cheshvan deficient, and so on until the end. But since we sometimes need to pay back from what we have more chalakim, there are two months that are different.

The normal goes in an order. Tishrei is always full, that’s how it begins. Teves is always deficient. From Teves onward it goes in an order, one full and one deficient: Teves deficient, Shevat full, Adar deficient, Nissan full, Iyar deficient, Sivan full, Tammuz deficient, Av full, and Elul deficient.

I simply laid it out this way because it fits the rhythm. But this is the order.

So if someone asks you two days Rosh Chodesh, one day Rosh Chodesh, the answer for all months of the year, except for Cheshvan and Kislev, is always the same. Right?

In other words, you can say that all months that have Yamim Tovim are always full. You can say that. Yes, but that’s not about that, it’s just a calculation. Right?

In other words, every month that before it is a full month has two days Rosh Chodesh, right? So Cheshvan always has two days Rosh Chodesh. The same thing Shevat, the same thing, sorry, the same thing Teves when it was before. Teves can be sometimes one day or two days.

But except for Teves, every month in the world cannot be. There are always two days Rosh Chodesh Adar, and Iyar, and Tammuz, and Elul, every single year. And the same thing, the opposite, others don’t have. Elul must still be in the same format. Okay.

I don’t know why it is, because just like I’m telling you, make another line, a half line, the same format. If you want, no problem. Do you understand what I’m saying? There are always two days Rosh Chodesh Elul and so on.

And regarding leap years for example, it also went in an order. The first Adar, and the second is deficient. It’s different. Meaning usually Adar is deficient, but the first Adar is full. Right.

Halacha 6: Marcheshvan and Kislev — Full, Deficient, In Order

Two months remain that we haven’t yet told about. What happens with those two months? Marcheshvan and Kislev.

This is how it rotates. Sometimes they will both be full, sometimes they will both be deficient, and sometimes the month of Marcheshvan will be deficient and Kislev full.

The three types have names. And a year in which these two months are full is called one whose months are full. A year in which these two months are deficient is called one whose months are deficient.

When one says the year that is deficient in its months, one means the two that can be changed, all the others already go with an order.

And a year in which Marcheshvan is deficient and Kislev is full is called one whose months are in order, that year is an orderly year.

It turns out that you want to know another thing, a year, a Jewish year, now we’re talking about a simple year, has three different counts of days that it can be.

A deficient year has only three hundred fifty-three days, a normal year in order has three hundred fifty-four days, and a full one has three hundred fifty-five days.

And remember, they said that the lunar year is three hundred fifty-four, but that’s only the average, because we learned that sometimes one must add or subtract because of the remaining chalakim.

So, a year doesn’t always have the same amount of days. Still before the leap year, understand? A leap year is the same thing, even a leap year can also be the three ways, so it turns out that the leap year can be either three hundred eighty-four days, which is the deficient one.

Halacha 7 — The Calculation of Days Between Rosh Hashanas

Speaker 1:

But no, here also comes in what we learned in Chapter 7, that there is when one adds two days, yes? The two days will have to be like a complete hour. Which two days? If Rosh Chodesh Tishrei is…

Speaker 2:

That doesn’t change anything, he said. It only tells us who doesn’t…

Speaker 1:

Good. The previous chapter doesn’t change anything for this.

Speaker 2:

Yes, but I’m saying, there was a mention that one should add two days.

Speaker 1:

There’s no such thing, one doesn’t add there, one pushes off Rosh Hashana. Because a year before…

Speaker 2:

No, I’m saying, a year before must be full in its months.

Speaker 1:

No, that has already done… A year after full in its months can be the year that otherwise would have been…

Speaker 2:

It can be yes, it can be no.

Speaker 1:

But that… I’m telling you, the answer is only that you don’t know that there stands the reason why there is there a rule of postponement. But to know practically what to do, you don’t need to connect the two things.

Soon already, you’ll already see in a minute how one knows which year is deficient and deficient. That’s the next halacha. But there are three types of years. First of all he calculated the names of the three types of years. And now he says how, when does one determine which year should be this way or that way. How one knows. Also how one decides.

For the same reason, but it’s not exactly for the same reason. He says within, “The way to know the year whether deficient, full, or in order, according to this calculation, take.”

Interesting, he says many times the word “according to this calculation”.

Speaker 2:

Right, there were other calculations that run differently?

Speaker 1:

No, logically, according to sighting. Logically, according to anything else. According to the calculation that is fixed, it goes differently.

Yes. Says the Rambam, “Know first the day on which Rosh Hashana was fixed for the year whose order of months you wish to know.” Once you know which day Rosh Hashana was fixed, whatever you want Chapter 6 months, you’ll know, which day is Rosh Hashana? “And know the day on which Rosh Hashana after it was fixed.” According to the same calculation from the previous chapters.

Yes. “Count the number of days between them excluding the fixed day of this one and that one.” You’ll count how many days there are still in the year except for the two Rosh Hashanas?

Speaker 2:

Not how many days.

Speaker 1:

Days means that there are days of the week, right? In other words, he’s going to say, if Rosh Hashana last week was Monday, and today it’s…

Speaker 2:

It can’t be Wednesday.

Speaker 1:

Anyway, it’s Thursday, there are three days in between, or the like. According to this you’ll decide such a thing.

“If you find between them two days, the months of the year will be deficient.”

“If you find between them three days,” it moved in the week by three days, “they will be in order.”

“And if you find between them four, they will be full.”

It makes more or less sense, because if there are four days, that means the year is very long, so one must have the full ones.

Speaker 2:

Here is, what you asked earlier when one pushes off, one pushes off, very good, then one puts in another day so that it should be a whole year. Here is where the days come from.

Speaker 1:

Yes, very good. Exactly, from here come those days. That’s the answer. How can one add a day to a year? One doesn’t add a day to the month of Elul. One adds, basically what one adds is Rosh Chodesh Cheshvan, and one makes Cheshvan full. That’s basically how one adds. Or one takes away, that means one takes away from Kislev. That’s basically what one can do.

Halacha 8 — Leap Year: Four, Five, or Six Days

Speaker 1:

“And in a leap year they said,” now you need to know that the rules are only in a simple year, then one goes by the two, three, four. But a leap year is completely a different order.

Speaker 2:

But a leap year simply has more days, a leap year always has more days.

Speaker 1:

So, “If you find between the day of its fixing and the day of fixing of the year after it four days, the months of that leap year will be deficient.”

“If you find between them five days, they will be in order.”

“If you find between them six, they will be full.”

Very good. That means since there is another month, another day is added.

Speaker 2:

Because technically two more days.

Speaker 1:

Why should one month bring so many days?

Speaker 2:

Because the leap month is always full.

Speaker 1:

So the leap month comes with thirty days. So think about it, the leap month one also made because one had extra days.

Speaker 2:

Yes yes, but also the leap month is always thirty days, so it’s two more days of the week, right? Because twenty-eight plus two.

Halacha 9 — Example from the Rambam

Speaker 1:

“How so?” And the Rambam gives an example, right?

“How so? Behold we wanted to know the order of the months of this year, and Rosh Hashana was on Thursday, and it’s a simple year.” Rosh Hashana is Thursday, and it’s a simple year. “And Rosh Hashana after it is on Monday, we find between them three days, we know that this year its months are in order,” three days.

“And if Rosh Hashana after it was on Tuesday,” what does that mean? There are four days?

Speaker 2:

Because it was full?

Speaker 1:

Yes, because one had to make Cheshvan full. But there’s another reason. For example, Rosh Hashana after it on Tuesday, if there is but the molad another half day, it already doesn’t count with that at all.

Speaker 2:

No, one already counts with that calculation.

Speaker 1:

What I’m saying means after that.

Speaker 2:

Exactly.

Speaker 1:

“And if Rosh Hashana in this year was on Shabbos, and the year after it on Tuesday, the months of this year would be deficient, and in this way you calculate for a leap year as we said.”

In short, it’s very simple and very clear.

Halacha 10 — Signs to Check the Calculation

Speaker 1:

Now one can learn another trick. That what we just learned, how one calculates, that’s how one calculates, but I’ll give you signs. Meaning, not that this is the main calculation, but there are signs that can check if you made a mistake, or you can more easily see according to the signs that you need to make the whole calculation, you’ll be able to simply look at the signs and know.

“You have signs that you can rely on them, so that you won’t err in the calculation of the order of the months of the year,” the Rambam does an extra kindness. He already said one way, I’ll give you an easier way, “and on the principles of this calculation and the fixings and postponements that we explained their way and these are they.”

He says like this, “Every year in which Rosh Hashana will be on Tuesday will always be in order according to this calculation, whether simple or leap.” It will always be, if it’s at all Tuesday, if Rosh Hashana was Tuesday, that year will be an in-order year, in other words, a calculation of half and half, deficient and full.

Speaker 2:

Calculation and words, right? It’s six deficient and six full, it’s in order.

Speaker 1:

Yes, exactly, that’s what in-order means.

“And if Rosh Hashana will be on Shabbos or Monday, it will never be in order, whether simple or leap,” meaning it will be more full than deficient.

Speaker 2:

He doesn’t say which.

Speaker 1:

You’ll know that it can’t be deficient. It can’t be in order. Then it’s like this, “If it’s simple it’s possible that it will be deficient according to this calculation,” it must be full. “And if it’s leap, it’s possible that it will be deficient according to this calculation.” Or in order.

But in order you made a mistake. If it was in order, you have some mistake in a calculation. If it’s leap, it can’t be in order, so it must be either deficient according to this calculation.

These are things that one calls like checks, right? Heuristics.

Speaker 2:

Not heuristics is a rule, but you want to know.

Speaker 1:

According to the principle, this is like signs or advice to check that your calculation was correct, or you can know only the first sign tells us actually what the year is, because the others are according to the year, but you still don’t know which of the other two it is.

Speaker 2:

Certainly, he says these are only signs.

Speaker 1:

It’s interesting like this, what does one need to have with the signs?

Speaker 2:

It makes it easier, it’s advice for calculating.

Summary: The Three Chapters and the Calendar

Speaker 1:

Until here are the three chapters. Now whoever has learned the three chapters can already make a calendar. And if he wants to make it a bit easier for himself, he can look in the Tur in the laws of Rosh Chodesh to see more certain advice how to make the calendar, to know that there are signs for every year what they’re called, and with a whole process, and it’s a bit easier, but the Rambam said the foundations of the calculation how it works.

Already, until here is Chapter 8.