The dyeing affinity of natural dyes to silk was studied, and investigations were made on the dyeing affinity and color fastness properties of natural dyes which are not usually employed on silk at present, such as, Prunus speciosa (trunk and bark), Cinnamonum (bark), Alnus (fruit), and Miscanthus (the whole grass). These tests were performed in order to help solve problems concerning the exhaustion of vegetable dye resources and to develop Kihachijo with a modern sense and color tone. See also AATA 21-627 and 21-628 for Parts 9 and 10, and 22-878 for Part 12. -- AATA