When you travel in Korea, you will see on the elevator button ‘F(four)‘ instead of ‘4‘. Some buildings don’t even have 4th floor or room number 4. Why? Sino number 4’s pronunciation is ‘사(Sa)‘ and this is the same as a Chinese word ‘死(사 Sa)‘ which means ‘death’. Some Koreans still believe if they use number 4, they will have bad luck. However some new buildings just write number 4 because less and less people believe this superstition.
Not even only number 4, but writing a name with a red pen is also forbidden in Korea. In old days, Koreans wrote dead people’s name with red pen, and in modern days some Koreans still believe that is not good luck. So, DO NOT use a red pen to write your landlord’s name! 😉