I saw the answer about regular dress shirts that the corners in the front bottom and the tips of the collar do not create an obligation to affix tzitzis to them, if I am understanding correctly this is due to their not only being on the same side, but also because two are folded over and also that it does not overall create a four-cornered shape that is clear to the eye. I have also heard elsewhere that when edges that end in corners are buttoned together all the way down so that the bottom visually creates an unbroken line, that negates the corners, so that even a tallis made for tzitzis would lose this obligation if buttons were added down the sides and fastened all the way down that way, is that correct? This is all in preparation for my main question, which is about a dress casual shirt made to be worn untucked, with side vents (slits created by leaving the bottoms of the side seams open by about 2-3 inches and hemmed/finished creating little right-angle corners forming these side slits that break the otherwise straight bottom hemline). From what I have heard, it also seems that the openings would have to be longer/"rov", to create an obligation for tzitzis. At any rate, any better understanding you could give of the prevailing opinions on all these aspects would be appreciated!

Shalom, Thank you for your question. The Shulchan Aruch (Orech Haim 10, 7) discusses a four corned garment, that has the sides sewn together with only the bottom of the sides not sewn together, leaving 4 corners. (Just like your shirt). The ruling is that if the majority of the side is sewn together, it is exempt from tzitzit. Only if the majority (towards the corners of the garment) is open, then it is obligated in tzitzit. The commentators discusses if the sides were not sewn together, but rather closed with buttons or hooks etc. The understanding of the Mishna Brurah is that if it is a button that can be easily undone, it is not considered as truly sewn, and is still called “open” – as opposed to a hook that is bent over and difficult to open, which is considered as a sewing. However, there are those (the Magen Avraham and the Shulchan Aruch HaRav) who oppose joining the sides (below half way) even with buttons, because of “morit eyin” – the appearance of seeming joined. Because of this, most people wear a four corned tallit katan that has completely open sides. However, there are those who wear a singlet like garment, which is sewn together under the armpits, but leaves the majority of the side open below that. Some people even then have a button or snap that joins the open sides together below the half way point, to keep the sides together, relying on the opinion of the Mishna Brurah. I hope this is of some help, Blessings.