In 1968, Japanese leading ink manufacturer Dainippon Ink and Chemicals (DIC) commissioned Mitsuo Katsui to create DIC Color Guide: a full-scale sample book comprising 641 color chips plus a mixing chart. Along with two other prominent designers—Ikko Tanaka and Tadahito Nadamoto—Mitsuo chose 600 basic colors from among 3,000 candidate colors and presented them in attractive and inspiring combinations. This work became a reference for all Japanese printing companies and earned DIC recognition as a leading name in the field of color engineering.