Also known as: ほうれい線
Lines or creases that appear on the sides of the mouth and extend toward the nose, commonly known as nasolabial folds. These lines become more visible when a character smiles or laughs.
Smile lines are often used to convey expression, age, or realism. They are sometimes simplified as short curved lines near the corners of the mouth.
Not to be confused with Wrinkled Skin (more general skin creases) or Crow'S Feet (lines around the eyes when smiling).