(FORTUNE Magazine) – AS DUSK SETTLES on Tokyo, sparkles of light blink atop a boutique-filled complex called Parco. Densely packed neon signs below engulf the area in a fairy tale-like glow. But this is real. This is the Shibuya district, where a onetime student radical and poet named Seiji Tsutsumi has created a retailing revolution. There are lots of stores in Shibuya, but it was Tsutsumi's trendsetting Seibu Saison Group that transformed a nondescript neighborhood into a glittery mecca of buying. Long before the cash-rich Japanese shopper became an international cliche, Tsutsumi spotted his countrymen's growing penchant for luxury goods. He was one of the first retailers to realize that young Japanese consumers were ready to spend, not save, because they had no memories of the near-starvation years following the war. In 1988, Seibu's department store chain became Japan's largest, with $5.4 billion in sales, edging past longtime leader Mitsukoshi Ltd. The entire company is expected to generate revenues of $28.3 billion for the fiscal year | ending next February 28. Its diverse holdings include a chain of Dunkin' Donuts restaurants, a credit card company, and the Seiyo Ginza hotel in Tokyo, where a single room can cost more than $2,000 a night. Last September, in its largest overseas acquisition, the group bought the 98-unit Intercontinental hotel chain for $2.15 billion. Tsutsumi built all this from a third-rate department store he inherited from his father in 1964. It was a meager stake considering the elder Tsutsumi's wealth. Yasujiro Tsutsumi made a fortune after World War II developing golf courses, hotels, and retail stores. He had numerous wives, mistresses, and children. In his spare time he got himself elected to the Diet, Japan's legislature, 13 times. The rebellious Seiji at first wanted no part of Yasujiro's wealth. He became an active Communist protester at Tokyo University. His father gave everything -- except the department store -- to Seiji's half-brother Yoshiaki, who is now one of the world's richest men. Japanese newspapers and magazines make much of what they see as bad blood between the brothers, but associates of Seiji insist their relationship is healthily competitive, not venomous. Tsutsumi labels the extensive press coverage ''ridiculous.'' Tsutsumi looks back on his college radicalism as one of the most influential periods of his life. Says he: ''Even now I tend to trust those who had doubts and who protested during their early years.'' He turned his youthful rebellion inward and began to write passionate -- and award-winning -- prose and poetry under the pen name Takashi Tsujii. He still puts aside some time at night to write, and he attributes much of his marketing acumen to his continued association with writers and artists. ''They go ahead of the rest of us,'' he says. ''They are performing a function like pilots.'' A gentle renaissance man to the outside world, Tsutsumi has a reputation for severity within his company. Sometimes he is called a cho wahn mahn. The later two words are the Japanization of ''one man,'' as in one-man manager. In Japanese, the prefix cho means ultra.