Regular haircut
Human scalp hair grows on average about one eighth inch per week or one half inch per month. Most clipper guards are numbered in eighths of an inch. The number of the guard denotes the number of weeks of hair growth left on the scalp when a clipper with a certain numbered guard is guided over the head with the guard in contact with the scalp. A #1 guard leaves 1/8 inch (3 mm), one week's growth of hair, on the scalp; a #2 guard leaves 2/8" (6.3 mm), two weeks' hair growth, on the scalp; a #3 guard leaves 3/8" (9 mm), three weeks' hair growth on the scalp; and so on.
Let's trim our hair in accordance with the socialist lifestyle
It was broadcast on state-run Korean Central Television in the capital of Pyongyang and clips from the program were later rebroadcast on the British channel BBC One. The program claimed that hair length can affect human intelligence, in part because of the deprivation to the rest of the body of nutrients required for hair to grow. However, although some researchers have proposed that brain and hair are in competition from an evolutionary standpoint, cutting hair has no influence on its rate of growth. It was part of a longstanding North Korean government restriction campaign against haircuts and fashions deemed at odds with "Socialist values".