Silk strings for guqin, sold directly by the silk string maker, Mr. Lawrence Kaster, available for purchase at his Etsy online store https://www.etsy.com/sg-en/listing/231573417/silk-strings-for-guqin-order-separately
According to Mr Kaster (posted in Facebook on the Guqin forum), "I am the only Silk string maker who welcomes Custom orders. I can do this because I work in small batches and have enough experience to suggest options for many other instruments."
(Disclaimer: I have no affiliation with Mr. Lawrence Kaster or his online store. Neither have I purchased or used his silk strings.)
