Implied Question: This is despite the fact that Avram was seventy-five years old when he left Charan (as stated in Bereishis 12:4). (How can the Gemara say he was fifty two when he left Charan if the Pasuk says he was seventy five?)

Answer: There were two different times when he left Charan.

Answer(cont.): This is apparent from the fact that during the Bris Bein Ha'Besarim he was seventy, and he was then living in Eretz Yisrael. After that he returned to Charan, and stayed there for five years, as stated in Seder Olam. In Shabbos (10a, DH "v'Shel") I have discussed this at length.

Opinion#1: Rashi implies (DH "v'Siman") that the second Beis Hamikdash was destroyed during the year after Shemitah, meaning the first year of the Shemitah cycle.

Opinion#1(cont.): Rashi implies that the Beis Hamikdash was destroyed in the four hundred and twentieth year since it was built. Being that most of the year had already passed, the Tana who is counting the years of the destruction does not count this year, but rather starts from the year after which is the second year of the Shemitah cycle. Accordingly, one should add one year onto the amount of years stated by the Tana.

Opinion#1(cont.): Additionally, Rashi explains that in Erchin (12b) the Gemara asks the following question according to Rebbi Yehudah. How long was the second Beis Hamikdash extant? It was extant for four hundred and twenty years. This means that there were eight Yovel cycles of forty-nine years each, meaning there are eight years left from those years. Together with the other twenty, this equals twenty-eight. This implies that the Beis Hamikdash was destroyed during a Shemitah year (not the year after Shemitah)!

Opinion#1(cont.): The Gemara concludes that the six years until Ezra went and was Makdish, meaning that previously he had not counted years of Shemitah, are not included. This means that the second Beis Hamikdash was destroyed twenty-two years after Yovel, which means it indeed was destroyed on the year after Shemitah.

Question#1: It appears that due to his sharpness, he was not careful. When he explained that the Beis Hamikdash was destroyed after four hundred twenty years, this is incorrect, as it was actually after four hundred and twenty one years, as is clearly apparent from the Gemara in Erchin (ibid.).

Question#2: There is another question. Rashi explained in Erchin that the Gemara is asking a question according to the Rebbi Yehudah. This is incorrect, as the question is according to the Rabbanan, and there is no question according to Rebbi Yehudah.

Question(cont.): The Gemara says as follows in Erchin (ibid.). Is it possible that the second Beis Hamikdash was destroyed during the year after Shemitah? Let us analyze this. How long was the second Beis Hamikdash extant? It was extant for four hundred and twenty years. This means that besides for the year of the destruction there were four hundred years, equaling eight Yovel cycles. This is like the Rabbanan (who say that the fiftieth year of Shemitah is its own year, and that the Shemitah cycle does not restart until the fifty-first year). There were also twenty-two years. This implies that it was destroyed in the year of Shemitah, meaning in the twenty-first year.

Text: There are some Sefarim that have the text that the destruction was in the sixth year of the Shemitah cycle (instead of the year of Shemitah, as we concluded above in c1). This is referring to the four hundred and twentieth year. The Gemara answers that this must be according to the opinion of Rebbi Yehudah, who says that the fiftieth year counts for both sides. (The Avodah Berurah asks the obvious question: Rebbi Yehudah holds there are eight extra years from the eight Yovel cycles. These eight years plus the remaining twenty years equal twenty-eight, meaning the destruction was during Shemitah and not during the sixth year of Shemitah! See Avodah Berurah's answer at length, which involves changing the text of Tosfos.)

Text(cont.): This means there are eight extra years from the eight Yovel cycles, with an additional twenty years. This equals twenty-eight years. In the four hundred and twenty first year the Beis Hamikdash was destroyed. This means that it was destroyed on the year after Shemitah.

Question#3: The answer that Rashi quoted that the six years of Ezra (before he was Makdish) did not count is a different answer. Rav Ashi concludes that even according to the Rabbanan the six years of Ezra did not count. If so, there was eight Yovel cycles and fourteen extra years (twenty minus six of Ezra). It must be that the Beis Hamikdash was destroyed after the four hundred and twentieth year, plus the extra year during which the Beis Hamikdash was destroyed, means the Beis Hamikdash was destroyed during the year after Shemitah. (In other words, instead of being the four hundred twenty first year, it was the four hundred fifteenth year, being that we subtracted six from the time of Ezra.) This implies that in the four hundred and twenty first year (including the six of Ezra) the Beis Hamikdash was destroyed.

Opinion#2: It therefore appears that Rashi retracted what he explained here and in Erchin, as I have explained.

Opinion#2(cont.): The Rashbam also says that certainly the Beis Hamikdash was destroyed in the four hundred twenty first year. When the Gemara says we should add another year, it is because the Tana does not count twenty one years including the Churban, but rather twenty one (full) years that the Beis Hamikdash was extant. According to this, the Gemara in Erchin can be understood as I have explained.

Question#1: However, it is difficult that he counts the four hundred twenty first year as a year in which the Mikdash was extant, while everywhere else the amount is only four hundred and twenty.

Question#1(cont.): The Gemara earlier (9a) indeed said that Persia ruled for thirty four years, Greece for one hundred eighty years, the Chashmonaim for one hundred and three years, and Hurdus for one hundred and three years. This adds up to four hundred and twenty years. However, the four hundred and twenty first year seems to be when it was destroyed.

Question#2: There is another difficulty. According to this, when the world commonly states that the four thousand year mark was one hundred and seventy two years after the destruction, they are lying! They should really be saying it was one hundred and seventy one years according to the Tana who holds that it was built for four hundred twenty one years.

Question#3: Additionally, the entire Gemara earlier regarding adding forty-eight years is based on the calculation of starting off with four hundred and twenty years. The same applies to the Gemara regarding adding three years. If it would be four hundred twenty one years, he should only be adding two years.

Question#4: Rabeinu Tam asks that according to both explanations (Rashi and Rashbam), how can we understand the Gemara's sign? "And the sign is the Pasuk, "For these two (years)" refers to taking two years away from each one hundred years, as per the opinion of Rebbi Yehudah and unlike the Rabbanan. This is unlike other signs that help us remember how many years to add or subtract (to get to the final amount). It should have merely told us a sign to add one year (as this is what the Gemara says one should do to figure out which year of the Shemitah cycle he is currently in), for example, by quoting the Pasuk, "He will be free to his house for one year!"

Opinion#3: Rabeinu Tam therefore has the following text of our Gemara, which is that of Rabeinu Chananel. "If a person does not know the year (see below), he should subtract two years or add five years. He should figure the general amount of years from the Yovel and small amount of years from the amount of Shemitah cycles. The sign for this is the Pasuk, "For this is two years of famine in the midst of the land, and another five years in which there will not be plowing or harvesting." This is not referring to the years after the destruction, but rather to the amount of years from the kingdom of Greece, as the beginning of their kingdom was forty one years into the existence of the second Beis Hamikdash.

Opinion#3(cont.): The kingdom of Persia was for thirty four years during the second Beis Hamikdash, and the Greeks ruled for six years before their kingdom spread (which are not considered years of Greece). This equals forty years. In the forty first year they started to count years from their kingdom. Accordingly, the third year of their kingdom was the forty third year of the existence of the second Beis Hamikdash. This was the first year of Shemitah according to Rebbi Yehudah, as in the beginning of the Beis Hamikdash they started counting Shemitah.

Opinion#3(cont.): This is why it says that if someone wants to know the years of Shemitah he should lessen from the amount of the Greek rule two years, and start to count years of Shemitah, or add five years to their amount. It is now understandable that the entire Pasuk is a sign for the amount to add and subtract (addressing question (j) above).

Opinion: Rabeinu Baruch in Sefer Ha'Terumah rules that the law follows Rebbi Yehudah who says that the fiftieth year is Yovel and the start of the next Shemitah cycle.

Implied Question: This is despite the fact that in Erchin (12a) and Rosh Hashanah (9a) the Gemara says that this is coming to exclude Rebbi Yehudah's opinion. (If the Gemara says this twice, why should we rule like Rebbi Yehudah?)

Answer: Even so, we still rule like Rebbi Yehudah. We find in Kesuvos (10a) that the Gemara says that this excludes Rabban Shimon ben Gamliel who says that Kesuvah is mid'Oraisa, even though we indeed rule that Kesuvah is mid'Oraisa. In Kesuvos (10a, DH "Amar") I discussed this at length.

Opinion: In Tosfos Rabeinu Yehudah there is also an implication that we rule according to Rebbi Yehudah. This is because he figures the amount of Shemitah years nowadays based on forty nine years per Yovel.

Opinion(cont.): This is how he explains Rashi in our Gemara. In the four hundred twentieth year of the Beis Hamikdash, the Shemitah cycle restarted. One hundred seventy two years after the destruction equaled four thousand years. If we add the four hundred twentieth year itself, this was one hundred seventy three years before the destruction. If we add the fifth thousand years and fifteen years from the six thousand years, this totals one thousand one hundred eighty eight years. If one takes away one thousand one hundred and fifty years using Yovel, and takes away two years for every hundred of these years, he receives twenty three years from the remainder of the Yovel years to add to the extra thirty eight years, equaling sixty one. Fifty six equals many (eight) cycles of seven, leaving five years. According to this calculation, the year five thousand and eleven should be the first year of a Shemitah cycle.

Opinion(cont.): According to the Rashbam who explains that in the four hundred and twenty first year the Beis Hamikdash was destroyed and this was the beginning of Shemitah, Shemitah would not start again until the year five thousand and twelve. This is also true according to Rabeinu Tam.

Opinion(cont.): If one figures that three hundred and eighty years before the destruction of the Beis Hamikdash the kingdom of Greece started, and one hundred and seventy two years after the destruction was the completion of the year four thousand, this equals a different of five hundred and fifty two years. If one takes away two years he is left with five hundred and fifty. If one adds to this the entire fifth thousand years and fifteen years from the sixth thousand, it equals one thousand five hundred and sixty five years. The fourteen hundreds are taken away in bunches of two hundred years (four Yovel cycles each), leaving one hundred sixty five years. One hundred forty of these are taken away in twenty seven year cycles, leaving twenty five. This leaves a remainder of four after counting three more seven year cycles. This shows that in five thousand and twelve Shemitah will start.

Implied Question: The Gemara in Sanhedrin (97b) says that Eliyahu said to Rav Yehudah, "The world will not last less than eighty five Yovel cycles, and in the last one Moshiach will come." Rebbi Yehoshua asked, "Will he come in the beginning or end of the last cycle?" Eliyahu answered, "I don't know." Four thouand and two hundred equals eighty four Yovel cycles. Our Gemara implies that after most of the last cycle (the year four thousand two hundred thirty one) he will come. (How can it be that he has not yet come?)

Answer: Rav Ashi concludes there that the Gemara means that until this time one should not wait for him, but afterwards he should wait for him.