First published in 1978, Taiichi Ohno’s book, “The Toyota Production System: Aiming to Manage Free from Economies of Scale” is a classic. I have never read it in English, and my rendering of his words from Japanese will no doubt differ somewhat from the existing English version of this book. This seemed to be an appropriate time to read and reflect on this book and the valuable lessons within. I believe Taiichi Ohno’s words and ideas can help us through the challenges of today.
He begins the book reflecting on recent history, at the time the oil shock of 1973 and the resulting years of low economic growth. The parallels with today are striking. He says that in such times:
“We need to get rid of the idea of “the more, the better” as soon as possible.”
This is because not only does mass production no longer work, it creates all of the various wastes. The development of the Toyota Production System came from the realization of the folly of economies of scale in their pursuit to achieve productivity levels equal to or better than the industry in the United States, half a century ago. This resulted in the development of two pillars supporting the Toyota Production System philosophy of “thoroughly remove waste.”
Taiichi Ohno says that in traditional mass production, “It’s as though production plans exist in order to be changed” due to various problems that occur in each of the processes and result in deviations from the plan and mismatch between outputs and inputs of these processes. His approach to freeing Toyota from economies of scale and planned mass production was to turn common sense upside-down. Instead of a the first process “making and moving” to the second process, the second process would go to the first process to take away only what was needed and this would be the “plan” for what the first process made next. This resulted in the kanban system and the downstream pull system essential to just in time and TPS.
Ohno explains the origin of jidoka, the second pillar of TPS, as the automatic loom which was invented by Sakichi Toyoda and could detect a broken thread and stop. Jidoka is “intelligent automation” and in Ohno explains that the meaning of jidoka at Toyota is “a machine with an automatic stop mechanism built in.” He names the fixed position stop system (assembly lines), the full work system (linked machining lines), the pokayoke (mistake proofing for any process) and safety devices as examples of how human intelligence is built into all machines, old or new, at Toyota.
Taiichi Ohno also makes an insightful analogy between baseball and teams in the workplace. There is a “just in time” and “jidoka” effect on individual skills, teams and the role of the supervisor as coach of these teams. The “just in time” is the effective linkage of various skills of the team members such as pitcher, catcher, and fielders in baseball. The responsibility of the coach is to make the whole system work, just like a winning baseball team. At the same time, “jidoka” is used to identify abnormalities against the standard work, just as individual baseball players may show weaknesses in their abilities and then receive intensive training by their coach. The role of the leader of teams is to balance team synchronization (just in time) with abnormality management and corrective action (jidoka).
“The purpose is cost reduction” is the heading of one section of this chapter, and Ohno clearly states that in order to thrive a company must work to reduce costs so that customers will continue to choose them. It was such a target to improve productivity against the benchmark of the United States which led to the development of the Toyota Production System.
“People become active when the target is clear. The same is true of corporations.”
In 1943 Taiichi Ohno was transferred to the automotive side of Toyota from the Loom Works. The architect of the Toyota Production System was not an automotive engineer. He had no prior background in automobile manufacture. This allowed him to look at the automotive manufacturing process with fresh eyes and also apply a perspective from an entirely different industry: spinning thread. When people say “we’re not automotive, TPS doesn’t work for us” they should remember that what we call lean manufacturing today owes more to thread spinning (jidoka), the Piggly Wiggly supermarket (kanban) and the efforts of Dr. Deming to teach PDCA and the scientific method than anything. These were the seeds, the automobile industry was merely the soil.
The first thing Taiichi Ohno did was to create flow within the machining factory. He did this by turning machine operators into multi-process handlers. Ohno observes that in the United States there are many trade unions within one company and they prevent people from working at multiple processes across job code boundaries such as welding and milling. He clearly and simply states that this limitation put in place by the labor unions left American companies no choice but to pursue cost reduction through mass production in order to lower labor cost per unit. More units must be produced per machine in order to absorb the depreciation, which in turn requires machines that are higher performance, leading to the planned mass production of make-gather-move. This approach to pursuing scale through volume and speed creates waste, says Ohno.
Creating flow in the machine shop at Toyota took several years starting in 1947 through the early 1950s. The young Taiichi Ohno faced challenges. He met “stiff winds” of resistance from the experienced machinists who thought of themselves as craftsmen. As he build flow lines of two, three and four machines per person he found many problems such as machines that did not stop automatically at the end of the cycle or machines that required an experience person run them because a lot of adjustments were needed. These problems guided the development of the system.
“I was young and very eager but I saw that pushing sudden changes over a short period of time was not a good plan so I decided to stay calm and proceed deliberately.”
The practice of leveling the production load came from Ohno’s realization that the factory needed to produce 1,000 vehicles per month smoothly and steadily, 40 per day for 25 days rather than to have no output for the first half of the month and then a large output at the end. He labels this “dekansho production” from the “dekansho song” which is a folk song that begins with the phrase “the first six months of the year is a life of dekansho dekansho, the next six months I spend sleeping.” The origin of the term “dekansho” is obscure but it is believed to be a corrupted form of the Japanese word “to work away from home” as a migrant worker.
The country western equivalent would be a cowboy singing about the months he has to spend on the range driving cattle, all alone, waiting to get back to town with his money to spend it on drink and such. The inspiration for heijunka was the Japanese equivalent of Hank Williams.
“I started by working within Toyota” on how to escape from dekansho production. Next he approached those outside Toyota (presumably suppliers, also possibly Toyota Motor Sales) which required listening to various requirements from these people, and “Depending on the situation we discussed how we could help by providing people, goods, money and various ways of cooperating” towards the goal of escaping from the “migrant labor” style of production, resulting in what we call heijunka today.
Taiichi Ohno identifies overproduction caused by the hoarding instinct and the security people feel when they have inventory. He calls for a revolution of awareness:
“We must not remain an agricultural people. We must become hunters and have the courage to acquire what we need, when we need it, in the amount we need. It goes beyond courage. I want this to become common sense in today’s industrialized society.”
The good judgment in the early years and the continued striving by this tough, caring man resulted in the innovative and counter-intuitive systems of just in time, kanban and jidoka which are the pillars of the Toyota Production System. Once again the automotive industry of today is fertile for a significant change. Whether the result will be a process innovation similar to the Toyota Production System, a product innovation or something entirely different will be revealed in the fullness of time. The leader of this revolution will not come with an expertise in spinning thread. Perhaps such leadership will come from an expert in spinning polymers, spinning public relations, or even spinning as Sufi meditation. It may take such a radically different point of view to help the automotive industry through its challenges.