What Is the Toyota Chief Engineer (Shusa) System?

This guide explains the Toyota chief engineer system, called 主査制度 (shusa seido) inside the company: what the role is, how its authority actually works, where it came from, and why other automakers have not been able to copy it. It draws throughout on the chief engineers' own Japanese-language books and oral histories, rather than Western descriptions of them.

A chief engineer is drawn from engineers who have spent a career in one functional area, such as engine, body, or chassis, usually rising to lead it. Such an engineer is then groomed and selected for the role over years. The chief engineer no longer sits inside any one of those functions and has no direct reports in them. What the role does have is the requirement to sign every engineering drawing before it is authorized. That signature, and the technical competence to back it up, is the source of real power. As Akihiro Wada, who spent over ten years as shusa, put it: "If the shusa says no, that drawing does not live."

The system has operated continuously since Kenya Nakamura was appointed the first shusa for the Crown project in 1953. Senior executives from rival automakers, including Ford, BMW, and Mercedes-Benz, came to Toyota to ask how the chief engineer system works. Other companies have a chief-engineer title, Wada observes, but not the functioning role. He considers the integrated shusa, grounded in deep engineering authority, particular to Toyota.

主査 (shusa): 主 (chief, primary) + 査 (investigate, examine). Literal meaning: "chief investigator" or "lead examiner." Toyota translates it as Chief Engineer (CE). The term reflects the role's integration and examination function, examining and signing every drawing rather than commanding.

1What Does a Chief Engineer Actually Do?

The Scope

The CE leads everything concerning the assigned vehicle: product planning, vehicle planning, sales planning, profit planning, industrial design direction, design engineering oversight, prototype and evaluation supervision, equipment investment decisions, production management coordination, and sales promotion. In his book Toyota Product Development, Adachi captures the scope with a line he attributes to a Toyota president: "For the assigned vehicle model, the chief engineer is the president, and the president is the chief engineer's helper."

In Automotive Planning and Development, Hori compares the work to "top management of a midsize company driving company management." By his account, a single midsize vehicle takes over 500,000 working hours for design and testing alone, more than 100,000 person-days once production engineering and factory preparation are included, and over 10 billion yen in development cost and equipment investment.

The CE Image and Concept Paper

In his book Toyota Chief Engineer's Work, Kitagawa describes the concept-creation process in stages. First, the CE gathers marketing information, sales-division input, quality data, and competitor analysis. From these, the CE forms what Kitagawa calls the "CE image" (CE像). This is a set of development keywords and a vehicle outline: key dimensions, performance targets, design image, selling points, and price range. At this stage, "cost and development-cost constraints are temporarily placed at the edge of the mind, and dreams and ideals are also included."

The CE image is expressed as a basic layout drawing, often a 1/5-scale package drawing that Kitagawa compares to "the floor plan of a house." This package drawing is the CE's primary artifact. It is the concrete mechanism by which the CE controls the vehicle's character. All engineering departments design to it.

The CE image is then adjusted through discussion with sales, design, engineering, production engineering, plants, quality assurance, and purchasing. This becomes what Kitagawa calls the CE concept (CE構想). This is the development-decision proposal submitted for top-management approval. In practice, the CE has already explained the contents to top management informally and obtained consent in advance. Unless there is a serious oversight, the formal meeting approves what has already been agreed.

Cost Planning (原価企画 / Genka Kikaku)

Cost is not an afterthought and not the finance department's problem. It is part of product development from the beginning. Kitagawa frames it as cultivation: "The CE must cultivate the field of cost honestly, steadily, and thoroughly, and achieve the cost target." The cost target is broken down by vehicle area, part, material cost, processing cost, tooling cost, and other elements.

Hori adds the engineering dimension: "Especially for reducing the cost of parts, the chief engineer needs the ability to reduce cost by going as far as the manufacturing process of the parts." The CE must study part structures, propose structures that are easier to manufacture, and possess the ability to reduce costs in a way that parts makers themselves accept. Simply bargaining down purchase prices is not cost planning.

Adachi provides a strategic example. On the Mark II program, the CE group deliberately held equipment investment to 70% of target sales volume and cut the investment amount 30% below initial proposals. The reasoning: lower per-unit depreciation would enable a lower selling price, which would drive volume. The cycle was self-reinforcing.

Groundwork Before a Program Is Approved

Much of a chief engineer's preparation happens before a program is officially approved. Hori describes building advance trial vehicles, testing new concepts, and checking technical feasibility well before the company has authorized the work. This is done informally, "by asking colleagues who were enthusiastic about improving performance, or by arranging to use leftover budgets from other projects."

This is standard practice. It runs on the chief engineer's networking, the relationships and reputation built across departments, rather than on authority. People pitch in voluntarily because they trust the CE and think the work is worth doing.

The Political Realities

Hori is unusually honest about the CE role's vulnerabilities. CEs can be removed mid-project by superiors in the Planning Department. In one case he describes, a veteran CE was replaced one year before production start, "after being responsible for more than three years from the start of planning." He also describes being personally removed from cost-estimation assignments when his honest numbers were higher than what management wanted to see.

The CE must manage upward as well as outward. Having the best concept means nothing if you cannot maintain a relationship of trust with the directors above you. This is the unglamorous reality behind the "responsibility without authority" principle.

2What Gives the Chief Engineer Real Authority?

For a role with little command authority over the departments, the chief engineer's real lever is approval. Historically, every engineering drawing, whether engine, transmission, body, or component, required the chief engineer's signature before it could be released. Nothing was authorized to be built until the chief engineer had signed off. That approval gate, backed by the technical competence to use it, is the source of the role's real power: a staff position holding a veto over what the line engineers produce.

No one could check every drawing in detail. Wada reviewed stacks of them each morning and worked by judgment. A messy drawing usually hid a struggling design. But his ninth rule names the real mechanism: "It may be impossible to review every drawing today, but design departments must always believe they are being inspected." The discipline mattered more than any single signature.

Wada is emphatic that chief engineers at other companies do not hold this approval authority. That technical veto over engineering output is what set the Toyota chief engineer apart.

The paper signature has faded with CAD and digital development, but the principle has not: the chief engineer still holds the approval every design must pass, now through digital workflows rather than a stack of drawings on a desk.

3What Makes the Chief Engineer System Work?

Akihiro Wada has perhaps the most expansive view of the chief engineer's role at Toyota: he held it successfully for more than ten years and was later elevated to executive vice president for engineering. On what makes the system work, he offers these personal insights from his oral history. He is as frank about the system's weaknesses as its strengths.

Technical competence. The chief engineer must be able to argue with engineers on technical grounds. Without this, the drawing signature is meaningless. The engineers will know the chief engineer cannot actually evaluate their work.

Deep expertise in one domain. The chief engineer must be someone who can stand equal to a department head in their home engineering domain. Wada calls this "the first condition." If you have that depth in one area, such as engine, body, or chassis, then the CE assistants (主査付き / shusa-tsuki) cover the other areas.

Experience across multiple model cycles. One model cycle is insufficient. The best CEs accumulate judgment across multiple vehicle generations. Wada spent over ten years as shusa. When modern CEs do only one cycle and rotate out, problems follow. A new CE who thinks "now I can build the car I want" may do what Wada calls "outrageous things." The organization, conditioned to follow the CE, will follow them in the wrong direction.

Oversight from above. The responsible executive (担当役員, tantō yakuin), the board-level officer in charge of that area of development, must check the CE's work. This is real oversight, not a rubber stamp: at Toyota these executives were themselves engineers who rose through the company (the board was entirely internally promoted until Toyota named its first outside directors in 2013), so they could genuinely judge the CE's call. It matters because the whole organization moves on the chief engineer's opinion. A wrong one carries everyone down the wrong path. Wada calls this the system's primary weakness: "The whole company moves easily on the shusa's opinion — easy to unify in one direction. The downside is the opposite."

Institutional culture. The company-wide culture must treat the CE's word as authoritative. This developed organically from Nakamura's track record, not from formal decree. Other companies tried to copy the role but could not replicate the culture. When Mercedes-Benz sent all their technical directors to Toyota, their questions focused entirely on "why does the shusa system work?" The answer is not structural. It is cultural, built over decades.

A succession pipeline. Ninety-nine percent of new CEs come from having been shusa-tsuki for that vehicle line. The best candidates are kept in the CE group long-term, not rotated too frequently. Wada maintained a system where "information was shared so the shusa could be replaced at any moment." The result was continuity, not dependency on one person.

4How Did the Chief Engineer (Shusa) System Originate?

Kenya Nakamura — The Founder

The chief engineer role traces back to Kenya Nakamura, who defined and embodied it as its first holder. Appointed by Eiji Toyoda as the first shusa for the Crown in May 1953, he was placed deliberately outside the existing departmental structure. What he established was not a written policy but a practice so successful it became culture. As Wada puts it, "Nakamura left such magnificent results that across the entire company, a mood developed that the shusa's word is the president's word. It spread as a kind of unwritten law." Adachi confirms the system "had no written regulations": it was carried forward by custom and results, not by decree.

The full account is in Kenya Nakamura, Toyota's First Chief Engineer.

Tatsuo Hasegawa — The Codifier

If Nakamura invented the practice, Tatsuo Hasegawa turned it into a scalable system. An aeronautical engineer who joined Toyota in 1946, he served as Nakamura's deputy (副主査) on the Crown, then became a chief engineer in his own right and led the Publica, Sports 800, Corolla, Celica, and Carina. Where Nakamura led by example, Hasegawa codified the role. He wrote the Ten Rules for the Chief Engineer (set out below) and established the Product Planning Office in 1965.

The full account is in Tatsuo Hasegawa, Architect of the Shusa System.

The Product Planning Office

The CE function is housed in the Product Planning Office (製品企画室), a staff department within the engineering division. This is the organizational home that lets the chief engineer carry product responsibility without sitting in the engineering line. Multiple CE groups share an open floor without partitions. As Adachi describes it, "consulting a neighboring chief-engineer group about past experience, similar problems, or surrounding information was part of daily life." The information-sharing was judged to outweigh any competitive-intelligence risk between programs. The office grew from roughly four to six chief engineers in the 1950s–60s to ten to twenty by the 1970s–80s, one per vehicle model.

5What Are the Chief Engineer's Guiding Principles?

Several Toyota chief engineers set down their own guiding principles. Hasegawa's came first and is the canonical set, reproduced below. Wada and, later, Kitagawa each wrote their own, covered in their articles.

Hasegawa's Ten Rules

Hasegawa codified his into "Ten Rules for the Chief Engineer" (主査に関する10ヶ条), a philosophical and demanding set:

Have your own plan. Do not arrive empty-handed, but do not over-dictate either. Hint gradually to build trust and direction.
Always learn broad knowledge. Expertise outside your own field lets you see a problem another way.
Cast a wide net. How the CE moves at the early survey stage can decide the project's fate.
Pour in all your wisdom and ability. Concentrate everything on the 5,000-hour project. When seriousness shows, people follow. Put your body on the line.
Do not find repetition tiresome. Reflect daily. Repeat your intent to collaborators at least five times.
Never blame others. You own the result even if it means changing the system. Authority has never existed. All you have is persuasion. If it is truth, it has infinite power.
Have confidence in yourself. Do not waver, or at least do not show it. In trouble, a good idea always comes.
The CE and CE assistants are a single persona. The CE is not a manager. There is no hierarchy in engineering. Correct how the work is done, never the result. When you want to scold, scold yourself.
Do not use tricks. Face, backroom deals, and rank never last.
The qualities a CE needs: knowledge, technical ability, experience, insight, judgment, decisiveness, magnanimity, composure, concentration, vitality, leadership, expressiveness, persuasiveness, flexibility, and "the desire called desirelessness."

Detailed commentary on each rule is in What Are the Toyota Chief Engineer Principles?

Wada's Ten Rules (心掛け / Kokorogake — "Things to Keep in Mind")

Wada wrote his own, separate set of ten, deliberately practical, a down-to-earth counterpart to what he found an overly lofty Hasegawa list (think constantly, give concrete instructions, decide fast, avoid large meetings, develop and trust the CE assistants). He and his interviewer note these apply beyond the CE role. They describe how any engineer should think.

The full set is in What Is the Toyota Chief Engineer Mindset?

Kitagawa's Seventeen Principles

Kitagawa (CE 1996–2005) compiled his own seventeen, built on three dispositions he held essential: curiosity, consideration for others, and imagination. They are covered in his article: Naoto Kitagawa — Toyota Chief Engineer's Work.

6What Does the Prius Case Reveal About the Chief Engineer System?

The first Prius (1993–1997) is the best-documented case of the CE system under pressure, and an unusual one in Toyota's history. It was Toyota's first hybrid and the world's first mass-production hybrid car. There was no existing model to copy and no proven technology to carry over: the powertrain, the key engineering decisions, and even the development method had to be created from scratch. That made it a far more genuine test of the chief engineer than a normal model change. It shows the role operating inside a chain of authority rather than alone.

Takeshi Uchiyamada led the G21 project as chief engineer with no prior CE experience. His lack of product-development preconceptions was treated as an asset for a car with no precedent. He owned the vehicle concept, ran the development, and negotiated his own terms with management: milestone management, with the right to push the schedule back if quality could not be built in. The team worked in a single room with all project information posted on the walls. Open big-room working and visual wall displays were not new at Toyota, but Uchiyamada systematized the room, the roles, and the practices into what became the obeya (大部屋) method. Production engineering was included from the start.

But the CE did not act alone. Akihiro Wada, as technical vice president, overruled the team's 1.5x fuel-economy target and demanded 2x. This deliberate stretch forced the move to hybrid power. He also made direct technical calls along the way. President Okuda set and locked the launch deadline. Uchiyamada owned the product. The vice president set the challenge and could have ended the project. The president committed the company. The system holds because each level trusts the one below it, and that trust rests on technical competence at every level.

The full development story is told in How Did Uchiyamada Build the Prius as Chief Engineer? It covers the stretch target, the battery and braking decisions, the prototype that would not move, the 24-hour cycle, and the launch.

7How Does the Toyota Chief Engineer Differ from Western Approaches?

A Western program manager coordinates schedule, budget, and communication across functions. The Toyota chief engineer's role differs in kind:

Approval over engineering output. The chief engineer's technical sign-off gates what gets built. A Western program manager holds no such veto.
Cost at the part level. The chief engineer owns genka kikaku, which is target cost broken down to material, processing, and tooling, not just a project spend.
The product concept and its sales. Adachi quotes a Toyota president: "The chief engineer himself should forecast sales, and then compete with Sales to see whose forecast is correct." The CE is accountable for whether the car sells, not only whether it launches.
A capability built by design. Command authority was withheld on purpose. As Adachi explains, "if the chief engineer persuaded sincerely, the other party's heart should move… that process ultimately trained the chief engineer."
Embedded in a system and culture. As noted earlier, Wada finds other firms have a chief-engineer title but not the functioning role.

8What Are Common Misconceptions About the Chief Engineer Role?

Misconception: The CE is a project manager with a different title. The CE owns the product, not the project plan. A PM coordinates timeline and budget. The CE decides what the car is, signs the engineering drawings, owns the cost structure, and is accountable for whether it sells.

Misconception: The CE should have line authority to be effective. Giving the CE line authority would destroy the mechanism that develops CE capability. The constraint forces persuasion, which forces technical competence, which builds the institutional trust that makes the system work. Toyota designed it this way deliberately.

Misconception: Anyone with strong leadership skills can be a CE. Technical depth is the first condition. The chief engineer must be able to argue with a department head on equal terms in at least one engineering domain. Without this, the drawing signature is a rubber stamp and functional engineers will ignore the CE's judgment. Leadership skills matter, but they are built on top of engineering credibility, not substituted for it.

Misconception: The CE role is heroic individual leadership. The CE room (主査室) is a team. One CE works with five to seven CE assistants (主査付き), each covering a different functional area. Both Hasegawa and Wada stress developing and trusting these assistants. Information is shared so that "the shusa could be replaced at any moment." The system produces continuity, not dependency on one person.

Misconception: Rapid rotation through the CE role develops more leaders. Wada is explicit that experience across multiple model cycles is essential. Modern CEs who do only one cycle and rotate out lack the accumulated judgment that makes the role effective. The system's health depends on CEs serving long enough to internalize the lessons of their mistakes.

Misconception: The system can be copied by creating the org-chart position. Other automakers have chief engineer roles. But without the drawing sign-off authority, the institutional culture that treats the CE's word as authoritative, the deep succession pipeline, and the informal groundwork done before approval, the role becomes coordination without teeth. Wada observed this across every competitor he encountered.

9How Has the System Evolved?

The chief engineer system has adapted through several organizational restructurings while preserving its core principle.

1950s–1960s: The Chief Engineer Office, with roughly 4–6 CEs. Nakamura and Hasegawa defined the role through practice.

1965: Hasegawa established the Product Planning Office (製品企画室) as a formal organizational unit, housing the CE function within the engineering division.

1970s–1980s: The Product Planning Office grew to 10–20 CEs. This was the era Wada, Adachi, and Hori describe in their accounts. It was the system at its most mature and least bureaucratized.

August 1989: The title was formally changed from 主査 (shusa) to チーフエンジニア (Chief Engineer), as part of a broader organizational flattening. The engineering division had grown to roughly 12,000 people and the title 主査 had spread to many departments. "Chief Engineer" distinguished the vehicle program leader, with sub-chief engineers beneath still called shusa. The term shusa continued in informal use and for sub-chief engineers under the CE.

1992: On September 25, 1992, Toyota restructured into four Development Centers: DC1 (FR passenger vehicles — Crown, Lexus LS, Mark II), DC2 (FF passenger vehicles — Corolla, Camry, Celica), DC3 (commercial vehicles and RVs — Land Cruiser, HiAce), and DC4 (element technologies — electronics and powertrain). Wada himself says "三つに分けた" in the oral history, referring to the three vehicle centers. DC4 was a shared technology provider, which is why "three" circulates. The center structure was refined over the following years rather than dismantled, and the chief engineer role carried through each change. Wada notes that the mid-1980s onward saw increasing specialization and subdivision that began to erode some of the old system's cohesion.

TNGA era (2010s–present): Under Akio Toyoda, the Toyota New Global Architecture standardized platforms across vehicle lines. In 2016 Toyota reorganized product development from the development-center structure into a product-based in-house company system: seven in-house companies, each with end-to-end responsibility for its product line. That is the structure in place today.

The core principle has survived every restructuring: one person accountable for the whole vehicle, leading through technical competence and persuasion rather than hierarchical authority. Whether it has been diluted in practice is a question the primary sources raise but do not definitively answer. Wada, speaking in 2008, expressed concern that shorter CE tenures and organizational complexity were weakening the system.

Summary

The chief engineer system assigns one senior engineer total accountability for a vehicle program, from concept through launch, while deliberately withholding line authority over functional departments.
Kenya Nakamura originated the role with the Crown project in 1953, and it spread as "unwritten law" on the strength of his results. Tatsuo Hasegawa later codified it into a system, with principles and the Product Planning Office.
The CE's real power comes from signing every engineering drawing. Without the chief engineer's signature, a drawing is not authorized. This gives technical veto power to a staff position.
The absence of line authority is deliberate. It forces the CE to lead through persuasion and technical competence, which develops the capability the role requires.
The CE owns the full product: concept, engineering, cost, production preparation, and sales performance. This is broader than any Western program-management role.
The system requires deep technical expertise, experience across multiple model cycles, institutional culture that respects the role, and a succession pipeline built through the CE assistant (shusa-tsuki) path.
No other automaker has successfully replicated the system, despite documented attempts by Ford, BMW, and Mercedes-Benz.

Frequently Asked Questions

What does "shusa" literally mean?

主査 combines 主 (chief, primary) and 査 (investigate, examine). The literal meaning is "chief investigator" or "lead examiner," reflecting the role's integration and drawing-examination function. Toyota translates it as Chief Engineer (CE).

Did the CE role come from aviation?

Several early Toyota CEs, including Nakamura and Hasegawa, had aviation backgrounds. However, Wada attributes the system specifically to Nakamura's practice at Toyota, not to any aviation precedent. The aviation connection shaped the individuals, but the system was built inside Toyota through results.

Does the shusa still sign every drawing?

The principle persists, though the mechanism has evolved with CAD and digital workflows. Wada, speaking in 2008, noted that complete review of every drawing was already impossible in practice. The key was that design departments believed their work was being inspected.

Why can't other companies copy the system?

No one thing makes the role work, which is why copying the org-chart title falls short. It rests on several things at once. The first is a chief engineer with deep technical ability. The second is the supporting processes and systems: the engineering-approval gate, target costing, and the assistant and succession pipeline. The third is a company-wide culture, built over decades, in which the CE's word carries real weight. Without all of them, the title produces a coordinator rather than a chief engineer.

How long does it take to become a CE?

There is no fixed timeline and no dedicated CE school, but by the time someone is appointed they typically have around two decades of engineering experience. The youngest CEs are usually in their forties, more senior ones in their fifties. CEs build careers in a functional engineering area, transfer to the Product Planning Office, train as CE assistants (shusa-tsuki), and eventually become CEs. The learning is OJT: assignment, mentorship, and the experience of struggling with real products. Kitagawa notes: "A person cannot learn the CE role only by reading manuals."

Is the CE the same as a "heavyweight product manager"?

"Heavyweight product manager" is the term Clark and Fujimoto used in their 1991 research for a strong leader who owns the product concept, and the chief engineer fits it. But the label understates the role: the Toyota CE also holds approval over engineering output, owns product cost down to the part level, and is accountable for whether the car sells. That is scope well beyond coordinating a project.

How many vehicles does a CE handle at once?

Usually one. A CE who carries more than one handles closely related vehicles that share a platform and components, not different types. Wada, for instance, ran the Celica, Carina, Carina ED, and Supra together, but those were related sporty and compact models (the Carina and Carina ED are essentially the same car). No CE would carry a truck, an SUV, and a luxury sedan at the same time.

What happens when the CE is wrong?

Wada identifies this as the system's primary weakness: "The whole company moves easily on the shusa's opinion — easy to unify in one direction. The downside is the opposite." The safeguard is the responsible director (tantou yakuin) above the CE, who must check the CE's judgment. But if that oversight fails, the organization follows the CE into error.

Sources and Provenance

This article draws primarily from Japanese-language sources by Toyota insiders. This is the distinctive sourcing that separates it from Western accounts of the CE system.

Wada Akihiro (和田明広), Oral History (2008). Five interviews conducted by Tokyo University of Science MOT, edited by Matsushima Shigeru and Odaka Kōnosuke. Wada served as shusa for over ten years (Celica, Carina, Carina ED, Supra) before rising to Executive Vice President. The richest single source on the shusa system's mechanics, history, and conditions.
Kitagawa Naoto (北川尚人), Toyota Chief Engineer's Work (トヨタチーフエンジニアの仕事). Kitagawa served as CE/shusa from 1996 to 2005. CE for the bB (developed prototype-less, without physical prototypes), the ist, and the Camry. Distinctive for the seventeen CE principles and the CE image/concept paper process.
Adachi Eiji (安達瑛二), Toyota Product Development — Strategy, Development, and Mastery of the Shusa System (2014). Covers the Mark II / Chaser / Cresta programs from 1973 to 1980. The narrative uses pseudonyms for all individuals named in it. The most detailed account of the "right to persuade" mechanism and the CE's strategic role.
Hori Shigeyuki (堀重之), Automotive Planning and Development: Process from Concept to Completion. Hori served as CE on fifteen vehicle models over fifteen years. Distinctive for cost-engineering depth, political realities (CE removal, honest-cost conflicts), and the below-the-surface work norms. Published by Grand Prix Publishing.
Uchiyamada Takeshi (内山田竹志) sources: Toyota 75-Year History (トヨタ75年史), JAHFA Hall of Fame profile, Toyota Times interviews, and GAZOO "Untold Story of Prius" series (narrated by Ogiso Satoshi). Cross-checked for the Prius development timeline.

The chief engineers and their books

Key concepts in depth

Encyclopedia

Shusa (Chief Engineer) — entry (compressed form of this guide)

Topic map

Chief Engineer (Shusa) — 108 sourced claims on the role