Oh washi tape, you addictive but utterly unnecessary stationery item, how I do love you
Washi was originally a type of hand-made Japanese paper made from mulberry fibres instead of wood pulp. It is very tough and is used in many traditional arts including origami, where it can be so thin as to be translucent, without degrading or losing its crispness.
It became popular as a form of decorative sticky tape used for journalling and giftwrapping, and has spread to western countries. Yes, of course I have a box of it in my art supplies, dammit.