Toyota’s supplier association, Kyohokai, was established to strengthen relationships and enable technical information exchange with core parts suppliers. This created an early institutional channel Toyota could later use to spread production methods and coordinate capability building across its supplier base.
As Toyota’s output grew, it organized non-parts suppliers too. Toyota formed Seihokai (molds, jigs, gauges) in April 1962 and Eihokai (construction and plant/equipment-related firms) in November 1962. These groups helped standardize management and technology improvements beyond component suppliers, supporting higher-volume, more stable production.
Toyota completed Kyohokai Hall in January 1963 as a dedicated venue for study meetings and conferences. Having a shared physical hub made regular training, problem-solving sessions, and cross-company coordination easier—key ingredients for later supplier industrialization under Toyota’s production approach.
During the 1960s, Toyota’s kanban method (a card- or signal-based “pull” system) spread beyond internal workshops. As Toyota aimed to reduce inventory and align output to real demand, it began extending pull-style replenishment to independent suppliers, which required suppliers to improve scheduling, quality, and responsiveness.
In the mid-1960s, Toyota developed a specialized internal capability to teach and troubleshoot production methods—often described as an elite consulting-style function that worked inside Toyota plants and at suppliers. This mattered because supplier industrialization under TPS depended on hands-on coaching (not just written standards) to raise quality, reduce waste, and stabilize processes.
Toyota’s factories increasingly demanded just-in-time (JIT) delivery, but major efforts to implement JIT inside supplier factories accelerated in the 1970s. This shift forced suppliers to invest in faster changeovers, better process control, and more reliable daily delivery—moving many firms from batch production toward continuous improvement routines.
In 1977, Toyota organized key suppliers into jishuken (voluntary study groups) to learn TPS practices through structured, peer-involved improvement projects. These groups helped spread practical know-how (like standardized work and problem solving) and created pressure for suppliers to keep improving, because results were reviewed and compared across the network.
In April 1983, Toyota merged the former Seihokai and Eihokai to create a new Eihokai with expanded membership and a stronger focus on cost and quality. By strengthening equipment and tooling suppliers alongside parts suppliers, Toyota aimed to remove bottlenecks in the wider production system (machines, dies, logistics, and plant systems) that could limit JIT performance.
In September 1983, Toyota and the UAW reached an agreement for the upcoming GM–Toyota joint venture that treated labor and management as partners toward shared goals. This agreement was important because it enabled Toyota-style practices—teams, flexible job roles, and stopping the line for defects—to be taught and tested outside Japan, reinforcing supplier and production learning linked to TPS.
Toyota and General Motors established NUMMI in 1984 in Fremont, California, and began production in December 1984. While outside Japan, NUMMI became a high-profile demonstration that TPS-style methods could work in a different labor environment, strengthening Toyota’s confidence in standardizing and teaching its production approach across an expanding supplier base.
By the mid-1980s, Toyota’s supplier network around Toyota City had been shaped by decades of association activity, training, and hands-on improvement support. The result was a production community able to deliver smaller lots, higher quality, and faster response—core requirements for Toyotism/lean production and a key reason Toyota could scale output while holding down inventory and defects.
By the late 1980s, Toyota strengthened joint activities linking the parts-supplier association (Kyohokai) and the equipment/logistics-oriented Eihokai. This mattered because lean production depends on the whole system: better parts flow requires reliable logistics and capable equipment suppliers, not only strong component makers.
Japanese supplier industrialization under TPS (1960–1985)