Siman 596

We are accustomed to blow after the prayer, to complete up to one hundred sounds, corresponding to the one hundred cries that the mother of Sisera cried, as the Aruch wrote. The Tosafot and the Rosh brought this in the fourth chapter of Rosh Hashanah. The Tur wrote in the name of Rav Amram that after the prayer – we sound a great teruah without a tekiah in order to confuse the Satan. We do not practice accordingly.

Our teacher, the Rema, wrote that after they have fulfilled their obligation with this—one should not blow anymore for no purpose. However, a minor, even if he has reached the age of chinuch—it is permitted to tell him to blow, and he may blow all day; thus far his words. Now, regarding the law of a minor, we explained it in siman 589, see there. However, regarding what he wrote that afterwards one should not blow anymore for no purpose—the Tur did not write so in the name of Rav Hai Gaon, see there. (For he brought proof from that which is said: when the shliach tzibbur finished the blowing in Yavne—a person could not hear his own ear from the sound of the blowings, see there. But the Rema follows the view of the Tosafot, that this refers to those who had not yet heard the blowings, as the Taz wrote in subsection 2, see there. And see Magen Avraham subsection 2 in the name of the Ra'avan, that when he no longer needs to blow—it is forbidden to handle the shofar due to muktzeh; see there, and it requires further study. And likewise what he wrote from the first day to the second day—requires further study. Examine it closely and you will find it simple.)