Shibugami is a hand-made mulberry paper that has many layers laminated together using tannin from the persimmon fruit. It is then smoked to preserve the paper and speed the curing of the persimmon.
The paper is mentioned in the Giyoshu military manual and it mentions applying oil and seaweed glue to the paper to strengthen it. The chemical alum and glue may be added to the persimmon tannin.
For oiled paper, the Giyoshu manual refers to applying 4 to 5 layers of tung tree oil and powdered lime and allowing it to dry.