Japanese self-adhesive stamps

I was soaking some Japanese kiloware the other day and I was really impressed with how easily they all came off the paper. Particularly the self-adhesive stamps. I've removed self-adhesive stamps from Japan from paper before but never enough of them to really appreciate how well designed they are.

The adhesive layer is separate from the face layer of the stamp and the two are bonded together with  a water-soluble adhesive. The only reason I can think of for designing the stamps this way is so collectors can easily remove them from their sticky backing. It took no more effort to remove these stamps from paper as it did to remove the non self-adhesive stamps. They came off beautifully every time.