Is the thread-bound book of Zhonghua Book Company Xuan paper?

No. The pages of thread-bound books by Zhonghua Book Company are not rice paper, but tough cotton paper or bamboo paper. Thread-bound book is a traditional book binding method in China, which is characterized by folding the pages into small folds, then sewing them together with threads through the creases of the folds, and finally binding them with the cover and the back plate.