"4" is unlucky, it is pronounced "shi" which means "death"
and same with "9" means "torture", some hospitals don't have the room number "4" They also don't like the number "13" (based on their religion), so FridayThe13th is also the unlucky number for them, so the number 4, 9, and 13 aren't on passenger planes.
The number 8 is a lucky number for Japan, they believe that it is because of the strokes, and what the shape of the number is. for them the number 8 means "better future"