This product was acquired from a deceased Japanese painter who passed away at the age of 100, 20 years ago. The "Gunryoku" (Group Green) and "Matsuba Rokusho" (Pine Needle Green) of that time were representative dark green mineral pigments of the green pigment family. The "Test Tube Gunroku" sold by the art supply store Ebisya in the early Showa era refers to natural green pigment refined into mineral pigments, sealed in a test tube, and sold with a label attached. The label, with a double red frame on a white background, is itself an important piece of evidence for authenticity. 〇 Gunryoku (Group Green) Refined by crushing and water-separating natural green pigment minerals, it has uneven particles and a natural astringency. A deep, dark green color. It is stronger than Matsuba Rokusho and darker than Byakuroku (White Green). Used for the dark parts of trees and backgrounds in landscape paintings, and for expressing dark green in clothing, it has high value as a research material. 〇 Matsuba Rokusho (Pine Needle Green) The color tone is a slightly bluish deep green among the green pigment family, a calm green like pine needles. It is darker than Byakuroku and slightly bluer than Gunryoku. The medium to dark color layer particles of the natural green pigment are slightly coarse, with natural depth and astringency, making it ideal for the trees, moss, and dark green clothing in landscape paintings. 〇 This item's form: The label (with a double red line) released by Kyoto Ebisya at the time is handwritten or printed with "Gunryoku" and handwritten with "Matsuba Rokusho". Gunryoku No. 11 14.27g Matsuba Rokusho No. 13 19.94 g Total 34g Especially, the natural mineral pigments in test tubes at that time have antique value and are sometimes traded at high prices as research materials and collector's items. (From AI research materials) The photos and explanations are all there, so please verify them thoroughly and we look forward to your purchase.