Toyota Production System: Professor Monden (Part Two)


Toyota  Production System

An indepth interview with Professor Monden about his renown work, Toyota Production System, and his ideas about Toyota and the spirit of kaizen in today's manufacturing world.

Yasuhiro Monden
Ph.D., Professor
Faculty of Business Administration
Mejiro University
(Professor Emeritus, Tsukuba University)

Please click below for Part One of the Toyota Production System interview.

Toyota Production System: Professor Monden (Part One)

Part Two:

Q. How has the Toyota Production System evolved over the years?

A. When I first visited Toyota and also initially Daihatsu motor company, that's a mini-car maker that belonged to Toyota but now they are a subsidiary company with Toyota owning more than 50% of their stock, I thought that this was a very severe way of manufacturing. Especially for their workers who had to work very hard, although they say this is efficient but not so hard. They said that they were trying to abolish the wasteful actions of workers, exchanging wasteful action with other value-added action but to me this was very hard work. However, since 1992 when Toyota established a new plant in Kyushu, the Fukuoka Miyata Plant, things have changed. Ergonomics, the field of human engineering, was introduced in to the operations management of Toyota's plants so that even women or elderly people could easily work in the plants without becoming fatigued. The main reason for why Toyota changed their production system to incorporate ergonomics was because of the difficulty of getting employees. That's one of reasons why they have established their plants in Kyushu, so as to be able to get more employees. Although most of their plants are located in the Chubu area near Nagoya, they have had to move to Kyushu to get workers. And with the decrease in younger people they have had to employ more women and elderly people.

Q. Since the TPS was first established is there anything that still continues the same at Toyota?

A. Yes, that's the spirit of Kaizen for continuous improvement.

Q. What are the biggest differences between introducing the TPS into a Japanese plant and an overseas plant?

A. In Europe and the United States, there is a special industrial relations, craft union. Each worker who works in a certain division must belong to that country's craft union. For example, a turner belongs to the turners' craft union, that covers the whole country, and a welder joins the welders' craft union. They are guarding their own working area, but the TPS assumes multi-skill workers so the multi-skill worker can not be cultivated under the craft union system.

Q. Is it possible to implement the TPS without multi-skill workers?

A. It's not easy but a partial implementation is possible. Even though the multi-skill worker is not used you can still introduce the system partially, for instance, the setup time reduction system and those kind of techniques could be introduced anywhere.

Q. Are there any other major differences between Japanese and overseas manufacturers?

A. There is big difference in the suppliers system and the relationship between the maternal company, in other words the final car maker, and the vendors. Until the end of the 1980s most of the suppliers were just the parts manufacturing divisions of the final assembly maker. This was the case for General Motors, Ford, and Chrysler etc. However, in Japan the suppliers have manufactured most of the parts outside of the assembly makers, and the KANBAN system, or parts requirement system, is entirely different. In Japan they have a very long term contract for using parts but it is said that the contracts between assemblers and parts makers in the United States used to be very short, just one year. However, after the 1990s many companies changed their system. General Motors established a big parts maker called Delphi, and they separated their parts division into another independent company and a long time contract relationship was introduced,

Q. What is the advantage of having a long contract?

A. You can have a more reliable relationship when you have a long term contract because, for example, the parent company can send their staff to teach how to make improvements. Toyota is always doing so and the KANBAN application is also very easy to implement. In addition, the assembler and parts maker can jointly develop custom parts. These kinds of things are difficult to achieve over a short period of time.

Q. What are the biggest differences between theory and practice when considering the implementation of the TPS?

A. I first taught about the TPS when I visited Singapore at the invitation of JICA (the Japan International Corporation Agency), a kind of governmental agency, to teach various companies. I also visited Thailand, USA, Taiwan, Argentina, Sweden, China and Austria. As a consultant I always examined if the production was going smoothly, that's the point I mentioned before, whether or not single piece or small lot production is being made or not. This is hardly achieved in practice. Also, when I look at the various processes I check to see if the balance of the workers' tasks is being achieved or not. If some people are very busy and other people are not so busy then that is not a good situation.

Q. Is it difficult to balance the workload?

A. If the production is being made with a big lot size then it is not easy to find a good balance. The bigger the lot size the harder it is to balance because inventories will be built up between the processes and these will hide the unbalance problem.

Q. The TPS has had a very big influence around the world but what influence has Toyota had on the Japanese manufacturing industry itself?

A. It has had a very big influence during the past 40 years, which is when the benefits of the TPS first became apparent. People discovered the TPS when the first oil shock hit Japan around 1972-1973, because they had to reduce costs. Everyone heard that the TPS was really useful to reduce costs and from that time the TPS became very popular around the country.

Q. What percentage of companies in Japan uses the TPS?

A. I think that most manufacturing companies know about what TPS is, theoretically at least, and have introduced the system partially. Even the chemical industry or those companies with large scale equipment are using the TPS as well.

Q. Is there any room still left for improvement in the TPS after all these years?

A. I believe so but I don't know what kind of direction they will go.

Q. What is the biggest challenge faced by the TPS for manufacturing in the future?

A. The shortage of human man-power is the biggest problem in Japanese plant management. One of the ways to resolve that problem is, as I said before, is to humanize the production system and employ women and elderly people. Another way must be the utilization of automated machines so that even though a company couldn't employee so many workers they can still respond to the growing demand of their product. But that is part of the field that the traditional TPS has not been challenging. It is the field of mechanical engineering rather than plant manufacturing, operations management or industrial engineering. This is one of the biggest challenges that manufacturing companies will face in the future

Q. What is your current project?

A. My current research topic is inter-firm relationship or network organization. That includes product manufacture, parts manufacturers and sales dealers of automobiles. That topic includes production management, organizational economics and managerial accounting. All three topics are my major fields that I have studied.

Professor Yasuhiro Monden Ph.D.
Professor Monden, in his Mejiro University faculty office, stands in front of his giant academic bookcase.

End of Part Two.

Look out for more interviews with Professor Monden and the Toyota Production System coming soon.
Interview by Lean Manufacturing Japan editor: Warren Harrod

Click below for a list of Professor Mondon's books that are available from

Prof. Monden Book Store of Toyota Production System