Red Ink is Prohibited in South Korea
In South Korea, if you use red ink to write someone’s name, that means this person has died, or you wish they would pass away. Be careful, as it is pretty much a death threat. Visitors have to be very careful when choosing red ink to write their name or sign a card. Two main theories are surrounding this fact. The first theory is that red ink is the same color as blood and symbolizes death, and the second one is related to Korean history. Grand Prince Suyang used red ink to write the list of his enemies.