The following are the standards for washi branded Hosokawa-shi
It should use only domestic kozo for raw material.
It should be made by traditional processes and tools.
* It should use only the extracted inner white bark, which is then boiled in plant or soda ash.
* No chemical bleach nor filler should be added to the raw materials.
* The beating should be done by hand or a process based on this.
* During paper making, viscous liquid extracted from the root of sunset hibiscus should be used for the “Neri”, and “Nagashi-zuki” formation style should be executed using a bamboo screen.
* The paper should be dried on a wooden or iron board. Characteristics such as the color, gloss and texture of traditional Hosokawa-shi should be maintained.