Samurai usually had to chop of their enemy’s head to prove their master that they actually killed the right person, not a woman or child. Additionally collecting more heads meant getting more stipend and promotion. However, after chopping the head, the samurai would always clean and put some light make up to the face to pay their respect to the dead person. At the same time, every samurai also usually put incense inside their helmets knowing that they may get killed and their head does not stink and does not bother their killer.
In situations when the samurai did not have time to chop the enemy’s head, they then used to cut the upper lip (to distinguish if the head is male or female).