Question: I was davening in a chassidishe shul and they omitted tachanun due to a Bar Mitzva. Was that right?
Answer: The Shulchan Aruch (OC 131:4) writes that one omits tachanun
in a shul when there is a chassan present or on the day of a bris.
R' Ovadia Yosef (Yabia Omer OC 1:27; 4:14; Yechave Daas 2:15)
writes that one omits tachanun on a day when a boy becomes Bar Mitzva,
too, comparing this both to a chassan and a bris. He
quotes R’ Ben Zion Meir Chai Uziel who writes that this minhag
highlights the importance of becoming Bar Mitzva, and of the significance of wearing
tefillin.
However, R’ Eliezer Waldenberg (Tzitz Eliezer 11:17)
disagrees, writing that omitting tachanun is not going to encourage
anyone to wear tefillin. R’
Nosson Gestetner (Lehoros Nosson 10:16) explains that the reason why the Shulchan Aruch does not
mention Bar Mitzva is because it is not the same simcha as a bris or chuppa.
R’ Yitzchok Yaakov Weiss (Minchas Yitzchak 8:11) notes that the
Minchas Elazar would omit tachanun when there was a Bar Mitzva in shul.
Nonetheless, he disagrees, writing that this is not common practice. R’
Binyamin Zilber (Az Nidberu 11:48) notes that the Ashkenazi practice in
Eretz Yisrael is to say tachanun (see Rivevos Ephraim 1:337; 3:86; 4:44:57; Ishei Yisrael 25:n79).
In conclusion, some Sefardim and Chassidim
omit tachanun in shul on the day of a Bar Mitzva while the main Ashkenazi
practice is to say it.