Question
Is a Kim Jon Un haircut mutar or assur, due to the grade 0.5 at the Peyot?
Answer
Shalom,
Without being a barber (and I had to look up what a Kim Jon Un haircut is) it seems that you want to know how much hair needs to be left at the place of the payot when a man gets a haircut. [Whether a person should get a haircut named after a political leader of dubious character, to say the least, is a whole other question that we won't get into here].
The place of the payot on the head is "the temples on both sides of the head at their juncture with the cheeks at the ears" (Concise Code of Jewish Law, 170). This is the hair above the ears, opposite the forehead, and including the sideburns - imagine the hair that is left after a chassid gets a haircut / shave. There are various opinions about the length of the sideburns [i.e. how far down the face is included in the payot], with some holding that one needs to grow long sideburns till the bottom of the ear (opposite to where the earlobe separates), and others holding that they only need to grow to the cheek-bone that is opposite the ear hole. Even though the Shulchan Aruch is strict in this question, those who are lenient have major sources to rely upon.
The length of the hair that must be left from the place of the payot does not have to be very long - the Mishna Brurah (Bi'ur Halacha 251) writes that all the hairs that grow in the payot area must be not be shaved completely off, but "ke'tsat min hake'tsat" must be left - that is the smallest fraction of hair. The Kitzur Shulchan Aruch writes not to "shave close to the skin". Some Rabbis say the hairs must be the length that is at least enough to turn the end of the hair back on itself, which is a bit longer, probably about 3 millimeters.
So, with this in mind, it seems that a very close shave above the ears on the side of the head is forbidden. If someone wants a short back and sides haircut, they should set the clippers to leave at least something of the hair - and they will still look quite dashing!
Blessings.
