Why you didn't hear 100 shofar blasts on Rosh HaShanah

Albert Joseph  Moore
The Mother of Sisera Looked out a Window

There is an old minhag to blow 100 shofar blasts on Rosh HaShanah. As I cite here:

The Aruch also mentions a custom to blow 100 blasts = tarat tashat tashrat each three times while seated {for a total of 30}, another during the Shemoneh Esrei on the seder of Malchuyot, Zichronot, Shofarot of the chazarat haShatz, for a total of 60. The additional 40 were thirty during the silent Shemoneh Esrei and 10 at the end. To cite a secondary source:

h) 100 - The ARUCH himself does not count just 60 Teki'os. He mentions that the custom is to blow 100 Teki'os altogether, corresponding to the 100 wails that Sisera's mother wailed for him when he did not return from the war with the Jews. (He apparently had a Midrashic source for these 100 wails.) It is from the Yevava (cry) of the mother of Sisera that we learn what a Teru'ah is (33b). The extra 40 sounds were blown as follows: 30 during the silent Shemoneh Esreh, and another 10 at the end of the Tefilah, before leaving the synagogue.

Others apparently connect it to the 101 letters in Sisera's mother's lament, but I am not sure how they reckon these 101 letters.

The Meshech Chochma has another take on the 100 blasts, which does not have to do with Sisera's mother. From the same secondary source:

The MESHECH CHOCHMAH (Parshas Tazria) cites another allegorical source for blowing one hundred blasts. The Midrash (Vayikra Raba 27:7) says that when a woman gives birth, she wails and cries out one hundred times. 99 of those cries are out of the conviction that she is going to die, and the final, 100'th cry is out of the realization that she is going to live after all. Similarly, we blow one hundred Teki'os on Rosh Hashanah. 99 are blown out of our fear of the judgment of the day, but with the one- hundredth we demonstrate our confidence that we will emerge from our judgment blessed with life.

How do we arrive at a 100 count?

A total of thirty sounds (as described above) are blown during the official shofar blowing ceremony which follows the Torah reading.

During three breaks in the silent part of the Musaf Amidah, another 30 blasts are sounded, ten (tekiah, shevarim-teruah, tekiah; tekiah, shevarim, tekiah; tekiah, teruah, tekiah) during each break. 

The same thing repeats itself during three breaks in the repetition of the Musaf, another 30.

Following Musaf, during a break in the Kaddish, another 10 blasts are sounded.

30
30
30
10
____
=100

However, the 30 is not really 30. It is 27! How so? Well, how do you count a tashrat? Is it tekia; shevarim; teruah; tekia, as four separate blasts? Or is it tekia; shevarim-teruah; tekia as three separate blasts.

This was what I was discussing in the previous post. There were some who held that a terua is what we call a terua and some who held that a terua is what we call a shevarim. Rabbi Abahu instituted in Caesaria to blow tashrat.

According to the simple reading of Rabbi Abahu in context; and according to the way that his contemporary Amora in the same location, Eretz Yisrael understood it; and according to Ravina, the redactor of the Talmud, this means that Rabbi Abahu was fulfilling blowing a terua according to both shitot. If so, shevarim and terua in tashrat are two blasts.

However, according to the setama degemara, and the way we pasken halacha lemaaseh, Rabbi Abahu actually blew this tashrat in addition to tarat and tashat. If so, what is the purpose of tashrat? The setama degemara answers that this is a third position in the definition of terura, that Rabbi Abahu was thinking that perhaps the Biblical terua was a shevarim-terua. If so, shevarim and terua are a single blast.

So take away 3 from each set of 30, and 1 from the final set of 10.