Comparing Eastern - Western Manufacture

In the east the inner fibres of the mulberry tree and other trees are used
to produce the extremely light and translucent papers of exceptional purity and great individual characteristics.
The method of " Nagashizuki," ( Fibres are floated in water and caught in the screen.) is very commonly used in the East.
The baste fibres are used compared to seed (namely cotton) fibres of European Paper Makers:

The Japanese papermaking method relies on the addition of a "Neri", a glutinous, starch-like substance, added to the water so that the fibres pulp increases the viscosity and also restrains the seeping of the water so that a controlled sequence of making paper can occur.
European papermakers make no such addition.
The Japanese use a flexible bamboo or fine reed screen held in position over a bamboo frame/mould.
It is this flexible screen (SU) which allows couching the delicate but strong fibres into a sheet.
Europeans use a rigid mould and deckle which dipped into the bath of water and fibres brings up to the surface the cotton fibres and then couch individually over a concave surface.