Tanaka is credited with developing the Muji concept together with Kazuko Koike (marketing consultant), and Takashi Sugimoto (interior designer).
•
Kenya Hara has been credited as key figure in further developing Muji.
Representative works include MUJI'S CD player (part of the permanent collection, MoMA New York ), the mobile phones "Infobar" and "neon" and the ±0 brand of household electrical appliances and sundries.
Following the death of his father in 1964, he led the spin-off of its logistics business to form the Saison Group, which eventually included the Seibu department stores, Seiyu supermarkets, Wave (a music shop), Parco (shopping complex), and the Muji and Loft variety store chains.
She is member of the Advisory Board for Muji (“Mujirushi Ryōhin”) since its founding and Professor Emeritus at Musashino Art University in Tokyo.
Bergne has worked with a wide variety of clients including Authentics, DeBeers LV, Driade, ENO, Epson, Lexon, Moulinex, Muji, P&G, Sassoon, Swarovski, Tefal, Vitra and WMF.