We have finished siman 2, in which the Chayei Adam listed some examples of the proper age to begin chinuch in specific mitzvos. The Chayei Adam wrote that the correct time for a child to begin wearing tzitzis is when the child is able to position the strings properly and follow the correct procedures for atifa (wrapping) and krias shema. Today, we will discuss the minimum size of the beged in order for it to be chayav in tzitzis.
Generally, the minimum shiur for a beged to be chayav in tzitzis is a beged large enough to be wrapped around one’s head and rov (majority) of one’s body; i.e., the entire upper torso. This is known as rosho v’rubo. This shiur is not necessarily estimated based on an adult, but rather based upon a person who is chayav in tzitzis. The Shulchan Aruch writes that this person would be a child who is already nine years old, and, therefore, a beged of such a size would be chayav in tzitzis. We see that the Shulchan Aruch assumes that the age of chinuch for tzitzis begins at the age of nine years old. However, many begin chinuch for a katan before the age of nine.
For a child under the age of nine years old, a beged which is large enough to cover his personal rosho v’rubo is sufficient. The Mishnah Berurah does point out that even if one begins chinuch for tzitzis before age 9, when calculating the shiur for an adult, one must use the beged of a nine year old to identify the proper minimum size.
The Mishnah Berurah writes that this minimum size is one amah in front, one amah behind, and one amah wide. The Mishnah Berurah holds that one does not count the area of the hole, but the Chazon Ish holds that if each of the shoulder straps are independently larger than the size of the hole, the hole can count. The Mishnah Berurah adds that, bedieved, one can use a shiur of three quarters of an amah.
In terms of calculating an amah into our measurements, since the shiur in question is derabanan, one may calculate an amah as 18 inches. Thus, a child should minimally wear tzitzis which in the front and back are a square of 18 x 18 inches. If one relies on the shiur of three quarters of an amah, that number would be 13.5 x 13.5 inches.
The Aruch Hashulchan holds that the shiur of rosho v’rubo is regarding the tallis gadol, which is meant to be worn in public, because one would not publicly wear a garment which does not cover the majority of their body. However, since a tallis koton is not seen by the public, even a smaller size would be sufficient. No other posek mentions this idea. However, Rav Yaakov Yeshaya Blau, in his sefer on chinuch, and Rav Neuwrith, in Shemiras Shabbos Kehilchasa, suggest relying upon the Aruch Hashulchan for the purposes of chinuch ( nuder the age of nine years old), if necessary.
Regarding the chiyuv chinuch for the mitzvah of tzitzis, the minimum shiur of the beged given to a child should ideally be 18 x 18 inches in the back and front. Bedieved, one may rely on a beged which is 13.5 x 13.5 inches. If those sizes are still not possible, one may rely on a smaller shiur until a child is nine. For a child under the age of nine years old, a beged which is large enough to cover his personal rosho v’rubo is sufficient.