There are certain additions that are added to the Amidah throughout the day and the night of Tisha BeAv. Of course the most common addition that we add to all our Tefilot during fast days is ‘Anenu.’ Our custom is to add the Anenu in all the Tefilot of Tisha BeAv beginning with Arbit, and of course the following day in Shacharit and in Mincha. Anenu is inserted in ‘Shomea Tefilah.’ When the Chazan repeats the Amidah, he would insert this Anenu in between the Beracha of ‘Goel Yisrael’ and ‘Rifaenu’.
It should be pointed out that if one forgets Anenu, he does not have to repeat the Amidah. Missing Anenu does not invalidate the Amidah.
There’s another addition to the Amidah that is specifically applicable only on Tisha BeAv. We insert the Beracha of ‘Nachem’ into the Amidah. ‘Nachem’ is a special insert that is put into the Beracha of ‘Tishkon Bitoch Yerushalayim’. It’s a special Tisha BeAv Beracha that talks about the destruction of Jerusalem, and how G-d, B’Ezrat Hashem, is going to console us with the rebuilding of Jerusalem. We end that Beracha with "Baruch Ata Hashem Menachem Tzion BiVinyan Yerushalayim."
Now, there is a great Machloket as to how many times one must mention ‘Nachem’. According to Maran in Shulchan Aruch, the Beracha of ‘Nachem’ is mentioned in all the Tefilot, starting with Arbit of Tisha BeAv, and continuing through Shacharit and Mincha. That’s the opinion also of Rav Chida(Rav Chaim Yoseif David Azulai, 1724-1806), and that it seems was and is the Minhag of Eretz Yisrael, which again, is to say ‘Nachem’ in all the Tefilot.
The Ashkenazim however, follow the ruling of Rama (Rabbi Moshe Isserles, 1530 - 1572), who says to only say the Beracha of ‘Nachem’ in Mincha of Tisha BeAv. He says this is because Mincha was the time exactly when the Romans came and lit the fire to burn the Bet HaMikdash. So it is at that point that we start to mention about the destruction of Jerusalem officially in the Amidah. Our Minhag is to follow the Ashkenazim on this, and we thus say ‘Nachem’ only in Mincha of Tisha BeAv.
Again, only Mincha Tisha BeAv, is where we say ‘Nachem.’ Now if somebody forgot ‘Nachem’, he has a few places where he can make it up. If he forgot it when saying ‘Tishkon Bitoch Yerushalayim’, he can make it up in ‘Shema Kolenu’. If he forgot in ‘Shema Kolenu’, he could make it up in ‘Ritze’ in the place where you say ‘Yaale VeYavo’ which is after the words ‘Avodat Yisrael Amecha.’ Now, in that place you can not say the Beracha with a Chatima (ending) of ‘Baruch Ata Hashem Menachem Tzion BiVinyan Yerushalayim’, but rather you would just say up until the Beracha and then continue ‘VeAta BeRachamecha’. If he still forgets to insert ‘Nachem’ at that point, he can still make it before he finishes the Amidah after the second ‘Yehi Ratzon’, right before the last part. Finally, if he forgets it there, he does not go back and repeat the Amidah.
This is a once a year item. Therefore, everyone should prepare themselves and be ready to say the Amidah with the proper inclusions in the Amidah on Tisha BeAv. Specifically, don’t miss out on the important addition of ‘Nachem’ in Mincha. It’s in the siddur, and one has to be cognizant while reading from the siddur. It’s in the middle of ‘Tishkon’, which is a Beracha that otherwise never sees an addition or insert. So be careful not to daydream, as it would be very easy to miss, since it is a once a year item. You can’t make it up, so again, make sure to be aware and make the necessary additions as mentioned above to the Amidah on Tisha BeAv.
