Ken Sakamura launched the TRON Project at the University of Tokyo in 1984, aiming for a computing architecture covering everything from washing machine microcontrollers to telecom switches. The family had five sub-architectures: ITRON for embedded real-time systems, BTRON for PCs, CTRON for mainframes and switching, MTRON for coordination, and STRON as a hardware kernel implementation. Hitachi manufactured the project's own TRON VLSI CPU as the Gmicro/200 series. The TRON Association, founded 1986, counted Hitachi, Mitsubishi, Fujitsu, NEC, Matsushita and Toshiba as members, with royalty-free open specifications and backing from MITI.

TRON Code, the project's encoding, defined 31 planes of 48,400 characters each, a theoretical capacity of 1,500,400 characters. By 1999 the B-right/V R2 release shipped roughly 130,000 characters across 14 planes, including Braille as a first-class plane years before Unicode 3.0 encoded Braille patterns. BTRON's desktop replaced files and applications with typed, linkable document parts and a directed-graph file model, essentially anticipating what tools like Obsidian and Roam rediscovered decades later.

In April 1989, the US Trade Representative's National Trade Estimate Report named TRON in Section 7 as a trade concern, citing Japan's plan to standardize school PCs on TRON and NTT's adoption of CTRON. TRON was never a Super 301 priority and no sanctions followed; the USTR even apologized to Sakamura over dinner after an investigation cleared the project. But Japanese manufacturers read the report as a political signal and abandoned BTRON anyway. The school adoption died by June 1989.

A 1999 biography of SoftBank founder Masayoshi Son by reporter Eiji Oshita alleges Son lobbied against TRON because TRON-based school PCs would have destroyed his business of distributing American software in Japan. The TRON Association's own magazine claimed a Japanese person, not an American company, destroyed BTRON via the USTR, and Sakamura later named Son directly on the TRON 30th anniversary site. Four months earlier, in December 1988, SoftBank's publishing division had already put out a book titled The Tron Revolution. A 1995 book by Scott Callon offers a counter-reading: BTRON was already failing on internal coordination problems, and the trade dispute was a convenient exit.

While BTRON died, ITRON spread invisibly: digital cameras including Casio's pioneering QV-10, Toyota engine control units, Japanese mobile phones and factory equipment. A 2003 LinuxInsider piece called it the most popular OS in the world, and the Yomiuri reports TRON-based systems still run in roughly 60 percent of embedded devices. Micro-T-Kernel 2.0 became IEEE standard 2050-2018, and in 2023 the IEEE recognized the TRON family with a Milestone plaque at the University of Tokyo. Microsoft even joined the TRON Project in 2003. Sakamura received the Takeda Prize jointly with Linus Torvalds and Richard Stallman. The desktop OS everyone watched failed; the kernel nobody noticed runs the world.