Writable distance: 250-350 m. "Sumi", black Ink is used for calligraphy, and good ink can produce great works. It is said to have started from China Yin era before 1500 BC. The main ingredients of Sumi are composed of soot, glue and fragrance, and the main characteristics of Sumi depend on the kind of raw materials. By the difference in features, you can enjoy shades of color and luster, blur, etc. The size of Sumi is displayed in units of weight of Cho. In the case of Japanese ink, 1 Cho type is 15 g as a standard, 2 cho type is 30 g, 10 cho type is 150 g. In the case of Karatsu, 500 g is used as the standard, 250 g for 1/2 type, 63 g for 1/8 type. Raw materials of ink is soot (carbon powder), glue, perfume, and Solid ink is made by mixing and drying them. Ink of good quality is not just black, but also it has a taste of seven colors in black. And when it is polished, it smells good and it does not sound. Sumi can keep the beauty of characters forever to the hearts of people. Kuretake Co., Ltd. is a Japanese stationery manufacturer. It is a manufacturer known for ink for calligraphy, brushes and so on. In addition, Kuretake manufactures pens, glue, paper products such as letter paper etc. In recent years, Kuretake manufactures crafts and art supplies such as calligraphy, watercolor paintings and has expanded its business abroad, including the United States and Western Europe. Good products of Kuretake will give you new discoveries and pleasures to your work.