1,157. How Many Shofar Blasts One Must Hear

Hilchos Shofar, Succah v’Lulav 2:10

Nowadays, when Rosh Hashana is observed for two days, the shofar is blown on the second day just as it is on the first. If the first day is Shabbos, those who were not in the location of a court sufficient to blow shofar on Shabbos (see halacha 2:9) may do so only on the second day.

Hilchos Shofar, Succah v’Lulav 3:1

One is required to hear nine shofar blasts on Rosh Hashana. This is derived as follows: The Torah says “teruah” (referring to sounding the shofar) three times regarding Rosh Hashana and the Jubilee year. Every teruah must be preceded and succeeded by a long blast (i.e., a tekiah). According to our tradition, all the shofar-blowings of the seventh month (Tishrei) – both those of Rosh Hashana and those of the Jubilee year - are one. Therefore, nine shofar blasts must be blown on each of these occasions as follows: tekiah, teruah, tekiah; tekiah, teruah, tekiah; tekiah, teruah, tekiah.