🚗 "Toyota cars had Toyota ashtrays, Nissan had Nissan ashtrays." Japanese automakers once insisted on proprietary designs even for trivial components like ashtrays. But now, as electrification and global competition intensify, the entire industry is accelerating toward parts standardization. How is Japan's manufacturing approach, long built on meticulous "suriawase" (mutual adjustment), evolving?

"Only Ashtrays Were Standardized": An Ironic Past

Japan's automotive industry long operated within a vertically integrated "keiretsu" structure, where automakers and suppliers collaborated closely on every detail. This "suriawase" approach produced high-quality vehicles but also meant that parts with identical functions had different specifications at each company.

Industry insiders joked that "the only thing automakers ever agreed to standardize was the ashtray." Steel thickness, tolerance levels, plastic compounds, semiconductor specifications: parts that could easily be shared were instead subject to company-specific rules. Suppliers had to accommodate different requirements for each client, adding costs and complexity that eroded the industry's overall competitiveness.

The European Threat and Signs of Change

The winds began to shift in the mid-2010s. German giants like Volkswagen, Daimler, and parts supplier Bosch united to standardize components and technologies, dramatically cutting development and production costs while maximizing economies of scale.

Sensing the threat, Japan's automakers responded in 2014. Toyota, Nissan, Honda, and 11 other companies, including truck makers like Hino and motorcycle manufacturers Yamaha and Kawasaki, formed the "International Standards Study Group" to explore unified specifications for steel, plastic, and semiconductors.

Electrification Accelerates Standardization

In the 2020s, the electric vehicle (EV) era has supercharged these efforts. EVs have fewer parts than combustion vehicles, making differentiation harder. Core components like batteries, motors, and inverters are prime candidates for economies of scale.

Under the Ministry of Economy, Trade and Industry's guidance, cross-company standardization discussions have intensified. Starting with rubber and plastic materials, the scope is expected to expand to more component categories in the coming years.

The Honda-Nissan relationship stands out. Merger talks collapsed in February 2025, but the two have if anything deepened their collaboration on development. In August 2024 they agreed in principle to work toward a shared e-Axle (electric drive system) over the medium to long term, though they buy from different suppliers, so the specifications are still being reconciled with those suppliers. Honda's main source, Astemo (formed in 2021 from the merger of Hitachi Automotive Systems and three Honda-affiliated parts makers, and renamed from Hitachi Astemo in April 2025), is owned 40 percent each by Honda and Hitachi with the remaining 20 percent held by JIC Capital; in December 2025 Honda announced it would buy an additional 21 percent from Hitachi to make Astemo a consolidated subsidiary. The two automakers are also working on common vehicle-control software, targeting deployment in new models by the late 2020s.

Note (as of August 2026): In June 2026 the Yomiuri Shimbun reported that Honda and Nissan were in final talks to share the electronic control unit (ECU) at the heart of their software-defined vehicles, with deployment possible as early as 2029, and that Mitsubishi Motors, 26 percent owned by Nissan, was set to join. Honda's consolidation of Astemo, meanwhile, has been pushed back to December 2026 because of procedural delays.

Die and Design Data Standardization Underway

Beyond physical specifications, design processes are also being standardized. In 2024, nine automakers, joined by die, steel, parts, and CAD/CAM makers, launched the "Automotive Die Manufacturing Efficiency Promotion Council" to standardize 3D design-drawing specifications. Membership has since grown to 35 companies.

Previously, machining attribute color codes, tolerances, and die component names varied by company. Die and parts manufacturers spent excessive time deciphering each client's rules, leaving insufficient time for quality and delivery management.

Standardization promises not only improved design efficiency but also faster training for die designers, a critical benefit as the industry faces severe labor shortages.

Light and Shadow of Standardization

Parts standardization raises legitimate concerns. The most prominent is expanded recall risk. When multiple brands and models share identical parts, defects affect far more vehicles.

For suppliers, standardization means fiercer competition. Without the "suriawase" barrier to entry, price competition intensifies, potentially accelerating industry consolidation.

However, standardization also improves supply chain resilience during emergencies. Having experienced the Great East Japan Earthquake and pandemic-era semiconductor shortages, the industry urgently needs flexible alternative procurement capabilities.

A New Form of Japanese "Cooperation and Competition"

This standardization wave doesn't negate Japan's automotive strengths. Rather, it represents a "select and focus" approach that clearly separates competitive and collaborative domains.

Automakers continue pursuing unique advantages in engine performance, interior quality, and driving experience while partnering industry-wide to reduce costs for materials and commodity parts. Amid the massive transformation of electrification, this standardization movement offers one answer to maintaining Japanese competitiveness.

The era of "only ashtrays being standardized" is already over. How does your country handle technology sharing and standardization among competitors in the auto industry?

References