Yamato has been manufacturing their Nori Paste since 1899 to save artists and craftspeople from having to make the paste themselves, as they had done for centuries before (and some still do).
Indispensable for professionals and loved by Japanese kindergartners who apply it with their fingers, it is an archival safe, acid-free, non-toxic paste made of plant-based starch. It is excellent for gluing washi paper and is also used by woodblock printmakers to modify and extend pigments, inks, gouache or watercolours, giving the colours more body and a more uniform appearance. 
 
As a glue it dries clear, is completely water reversible and will not alter the character of papers like other glues can, maintaining the translucence, colour and supple surface of washi, from robust Chiyogami and Katazome-shi to thin and delicate tissue papers. The glue can be mixed with a little water if necessary to make it easier to apply, and it is relatively slow-drying so papers can be slid and repositioned as required. As Nori paste is water-soluble it can be wiped or washed off easily and re-wetted to remove paper in conservation projects. 
An ideal adhesive for all sorts of paper craft projects, book binding and chine colle.
(The smaller tubes come in green, yellow pink and blue, but the glue is the same in all of them.)