Minimum Size of Talis Katan
My teenage son refuses to wear regular sized tzitzis, as they cause him discomfort, what is the most meikal shitta in the poskim of how small tzitzis can be?
Shulchan Aruch in O:C 16:1 codifies that the minimum size of a talis katan is a garment which could cover the head and most of the body of a child [the age of nine – mishna brura]. The Rama adds that this is on condition that the one wearing the tzitzis would also not be embaressed to wear such a garment in public. This is refering to the mode of dress in the times of Chazal where the talis katan was their main upper garment, in place of our shirts. In our day and age when the average person would not go out with our style talis katan, there are those who question the permisibility to make a bracha on such a talis katan. The Mishna Brura [biur halacha siman 16 s.v. lashuk] defends the common practice that we make a bracha on a talis katan even in our times. The Aruch Hashulchan suggests that being that our talis katan is worn exclusivley with another shirt, it no longer has the above requirements and is a fulfillment of the mitzvah as is, even without the above minimum sizes.
Practically speaking, the Mishna Brura [16:4] brings two opinions as to the minimum size for a talis katan. The Sefer Pri Haretz holds it must be 3/4 amma height and 1/2 amma width. Both the front and back must have these dimensions, without the neck hole. The Mishna Brura brings a more stringent opinion which requires a full amma by a full amma. One who is lenient has what to rely on as stated above, but should not rely on a 1/2 amma width, as many achronim [see m.b.] take issue with this size. the width should ideally be a full amma, and at least 3/4 of an amma, which is the shiur for minimum width brought by the Artzos Hachaim [Malbim], see Shaar Hatzion 8, in the name of Tshuvos Lev Chaim [Palagi].
Translating these shiurim to modern measurements, would depend on the well known dispute between the Chazon Ish and R’ Chaim Noeh. According to the Chazon Ish an amma is 58cm/23inch, while according to R’ Chaim Noeh an amma is 49cm/19.5 inch. It follows that to fulfill all opinions a tallis katan would require 23 inches by 23 inches on each side. The most lenient opinion would be 15 inch by 15 inch on each side [3/4 amma x 3/4 amma – R’ Chaim Noeh]. Tzitis which are 18 inches wide and 40 inched long would satisfy this opinion.