Taiichi Ohno devotes fully half of his book to chapter 2. Titled “The Application of the Toyota Production System” is one hundred and one pages long and it provides the body of practical knowledge on what we call lean manufacturing today. We will study it not all at once but in manageable chunks.
There are 38 sections within chapter 2. I have grouped them into the following themes, by order in which they appear:
- 6 sections on fundamentals of shop floor management
- 12 sections on material flow
- 5 sections on information flow
- 11 sections on overproduction
- 4 sections on management as ninjutsu (art of the ninja)
In this article we will cover the first three sections only.
Taiichi Ohno was not a writer of books. This book was written by ghost writer Setsuo Mito and was most likely the result of a series of interviews through which Ohno’s ideas were captured on paper. I am sure that the editors did not ask Taiichi Ohno, “If you had only 101 pages to explain the Toyota Production System, what would you say?” but in effect this is what we have in chapter 2.
Can You Ask “Why?” Five Times?
Ohno begins the chapter begins by challenging the readers if they can you ask ‘why?’ five times? “It is easy to say, hard to do.” He goes on to demonstrate with the classic example of the machine which stops functioning.
Why did the machine stop?
It overloaded and blew a fuse.
Why did it overload?
The lubrication on the bearing was insufficient.
Why was the lubrication insufficient?
The volume of lubrication from the pump was insufficient.
Why was the pump not pumping enough lubricant?
The rotor of the pump is worn and loose.
Why is it worn?
There is no strainer so metal shavings got in.
Not to challenge the master, but the reply to the fifth question should be “metal shavings got in the pump” which would have led to a sixth “why did the metal shavings get in?” to which “there was no strainer” would have been the answer. This is a case in point that the “5 why” principle must be followed in spirit and not in letter; often we must ask “why?” many more than five times to complete a thorough investigation of even simple problems.
Ohno’s main point is that if you stop asking why too early your solution may be to replace the fuse or to replace the pump rotor, neither of which would be long-term root cause corrective actions. He states:
As a matter of fact, we could say that the Toyota Production System came about as a result of the sum of, and as the application of the behavior by Toyota people to scientifically approach matters by asking “why?” five times.
He goes on to explain how the systems of jidoka, just in time, heijunka, visual management and kanban all came about as a result of questioning, “Why can’t we..?” have one operator run multiple machines, deliver goods just in time, prevent overproduction and so forth. Ohno makes his point again at the close of the section, that while he certainly values data he values facts that can be found on the gemba (“actual place” or shop floor in case of manufacturing) above all because only these facts can result in effective countermeasures.
The next section is called “thorough analysis of waste” and Taiichi Ohno sets down two fundamental principles for this:
- Improved efficiency is only meaningful when it leads to cost reduction. This requires producing the required amount with the least resource.
- Efficiency improvement must be looked at not only at the level of individual people, lines staffed by teams of people, and groups of these lines but as efficiency of the entire system.
The 7 Types of Waste
He puts the above two points into manufacturing-specific terms and focuses on labor productivity but they represents a broader explanation of his two fundamentals for thoroughly analyzing waste. Doing only the work needed to achieve the desired output, and making only what the customer needs are the two parts of Ohno’s definition of true efficiency. He uses two versions of the same equation to communicate the notion that waste is inherent in the work we do. The translation is something of a nightmare since 仕事 means “work, job, occupation”, 作業 means “work, operation” and 働き means “work, activity”. In any case the idea is clear:
Current capacity = work done + wasted effort
Operating = working + wasting
The Toyota Production System aims to improve efficiency toward 100% by reducing the resources required to make only what the customer needs. Thoroughly taking out waste is a precondition to implementing the Toyota Production System. Taiichi Ohno goes on to define the 7 types of waste as:
- The waste of overproduction
- The waste of waiting
- The waste of transportation
- The waste of processing itself
- The waste of inventory
- The waste of motion
- The waste of making defects
Ohno states that by taking out these wastes fewer people will be needed to do the same work, and that the removal of waste from work is an activity which respects people by making the work more meaningful. He is aware of the criticisms of this approach in that many companies use it to reduce employment. He states that it is the responsibility of management to make good use of the people freed from their jobs through kaizen by bringing in or finding other meaningful and productive work, rather than opportunistically cutting cost through layoffs or by promoting early retirement.
Ohno’s Philosophy of Gemba
Taiichii Ohno begins the next section by saying “I am a complete gembologist.” There is no other pithy translation for gemba+ism (現場主義) or gemba+ist (現場主義者). Perhaps colloqually “gemba guy” could work. Other expressions in English that approximate Ohno’s philosophy of gemba include:
- On the spot
- Front line
- Show me
- At the scene
- On location
- To the source
If his gemba philosophy were an -ism he would be a gemaist, one who believes in gemba. However as an an -ology the gembologist would be one who studies the gemba. I think this is what Taiichi Ohno is saying that he is: a student of the gemba, through and through.
He became a gembologist when in his early days at Toyota, but sees even greater importance in going to the gemba to get infromation as a senior manager. How did he become a complete gembologist? During World War II when the skilled machinists were called away from the factory to the battlefield, one of the first things Taiichi Ohno did upon transferring from Toyoda Boseki (spinning) was to require that standard work be documented. The men and women in the Toyota factory were brand new, making the need for standard work even greater. Ohno writes:
That experience of documenting standard work, which is the basic foundation of a production operation, was the beginning of my 35-year journey of developing the Toyota Production System. This was also the starting point of my gembology.
Ohno concludes the section by saying that like the andon lamps, the kanban cards attached to a container of goods and other visuals that exist at Toyota or any good company as part of the visual management system enabling gembology, standard work documentation must be visual and easy to understand. Ask why, pursue true efficiency, remove waste, go to the gemba and document the standard method so that the norm becomes visible. This is how Taiichi Ohno defines shop floor management at Toyota.
Read article on chapter 1 of the Toyota Production System by Taiichi Ohno.
Buy the Toyota Production System in English.