Translation:Shulchan Aruch/Orach Chaim/12
12: Things that Invalidate Tzitzit.
1 If all the strings on the corner have torn, and there remains upon them enough to tie all of the torn strings together, then they are kosher, and if not enough remains to tie them together, even on only one of those that has torn completely, they are invalid. Therefore, since every one of them is doubled over to make two, if two ends have torn off then it is invalid, because it could be that one string has torn. And according to our practice - which is to be careful when making the tzitzit to place a mark on the four ends in such a way that these four ends are always on the same side of the knot, and the four ends are on the other side – if two ends tear off on the same side, it is kosher, because certainly these are two strings, and each one still has its second end which is more than And according to Rabbeinu Tam, it is only accepted in a case where two complete strings remain – meaning four ends which each have a full 12-knuckle length. Then it is accepted when the other two tzitzit have torn – if they still have "enough for a loop". But if three threads have torn, even though they still have "enough for a loop", they are invalid. And because of this, when three ends have torn, if at the time the tzitzit were made he was not careful to ensure recognition of the four ends that came from one side of the knot, we are concerned that perhaps every end is from one string, and therefore there is only one complete string left. So because of this doubt, it is invalid. However, if only two ends have torn, they are kosher if "enough for a loop" remains. And the law follows the first opinion. However, it is good to be concerned for Rabbeinu Tam's opinion where possible. (Gloss: And our custom is like Rabbeinu Tam) Aguddah, Chapter 15. Gloss: And all the more so, if he was precise to ensure recognition of the four ends that come from one side, and three strings tore on one side, then it is invalid, because then it is certain that three threads have torn. And if they tore on two sides, it is also invalid, due to the concern that possibly three threads are involved (Beit Yosef in the name of ben Habib).
2 In a case where "enough for a loop" is needed, and due to the strings being thick, one is unable to form a loop with them, and if they were thin, there would "enough for a loop", it is kosher.
Gloss: And one measures with average threads (his own words).
3 "Enough for a loop": According to Rashi – from the "branch". And according to the Ri, even if the entire "branch" was severed, and there only remains "enough for a loop" from the tassel, it is kosher. And the world custom is according to Rashi. And when it is impossible, one can rely on Ri.