The age of old rice paper can be known from the appearance of yellow dots.
If the rice paper was 1300 years ago, it would have been too brittle to move!
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Although I haven't seen the real thing, it's probably a framed thing. Of course, it's very thick with the heart of the painting, holding paper or moving paper, and finally holding the back (sometimes holding two or three layers) and the paste used.
But this is definitely not something from 1300 years ago. Xuan paper 300 years ago was generally brittle.
When I say old rice paper, I mean it has been used for several years, usually twenty or thirty years, so it can be called old rice paper. Thick rice paper is not as thick as old paper, but some leather paper and some low-grade paper for mounting are thicker.