Also kaiki.
It is a woven silk fabric made with pre-dyed threads, which is often used for linings or umbrellas. Koshu-ori comes in a variety of types such as plain or stripes or shot silk.
Koshu-ori has been used for zabuton because of its unique nice and soft texture.
The woven cloth from China inspired ancient Japanese people to make their own woven cloth like China in the early modern period. That’s why koshu-ori was born. At that time, the woven silk fabric was called gunnai-ori because the old name of the producing area was gunnai, and gunnai-ori appeared in the novel of ‘The Life of an Amorous Man’ written by Ihara Saikaku during the Edo period.