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  • Writer's picturehidet77

Structure of Muda

In my last article, I talked about the importance of focusing on process structure and dynamics on the shop floor. There are many structures on the shop floor. The most important one to understand Toyota Production System is the structure of Muda (Waste). This article is about the structure of Muda.

When we talk about value-add work and waste, I am not going to say that Taiichi Ohno or Toyota was the original discoverer of this concept. The concept itself is widely accepted. Yet, when it comes to actual elimination, Toyota did a far better job than anybody else. Why? I believe they understood the structure of Muda (Waste). Or their spatial cognition of the shop floor or the field is different from usual. Such spatial cognition contributed to the elimination of Muda.

The structure of Muda starts with the starting and ending points of the value-add work. It might sound strange to mention these “Starting and ending points.” TPS people frequently use these starting & ending points for different structures. The standardized work starts with defining the starting point of work. Standardized work is not practical without a clear definition of where the starting point is on the shop floor. There is another terminology called “fixed stopping position.” TPS is famous for stopping the line. But that does not mean it could stop anywhere unless there is an emergency. It needs to stop at a fixed position, which is the end of takt time; otherwise, non-problematic processes will also suffer from random stopping. When we start the time study to create the standardized work, what is essential is the breakpoints of each work element. Breakpoints are the starting point of each work element. Breakpoints are these moments in work, like touching a material or switch or the feet starting to move. Unless we have a clear definition of these points, the time study will become unstable and unreliable. Without these points, walking and work mixes with other activities (My common mistake). The standardized work will become just a list of tasks without showing any dynamics of work. You will not be able to highlight the Muda. Starting & ending points are not ceremonial activities, like the bow before & after a Judo game, but rather a datum point of work structure.

I believe that Toyota discovered two essential characteristics of the starting and ending points of value-add work early in their journey. The first is that the exact location or the presence of these points is incredibly subjective—words or numbers can’t communicate the precise location or the presence. The person must learn to see it. Otherwise, the Muda is the same as a ghost. People might be screaming that a ghost is here. However, nobody can actually see it. They repeat that there is Muda, like some dark magic. Second, the quantity of these points is massive. Because of these two reasons, it became necessary for the leaders to continuously go to the shop floor to coordinate the cognition on Muda’s starting and ending points. The form of communication by these coaches was never direct. Sometimes they might be just staring at a process. But that is because the student side must develop the eye to see more waste. They can’t keep relying on the coach; otherwise, the organization will not attack the massive Muda. The attitude of continuous questioning of where precisely the Muda begins and ends is what the coaches are trying to communicate.

By connecting the two points forms a line that represents value-add work and waste. Here I visualize some thoughts.


This arrow represents value-add work. Once, I met a plant manager who claimed that “everything, since the material enter this plant until the product shipped to the customer, is value-add work.” I thought that such an opinion was an endangered species, but there are many similar sub-species. Like, “We are full capacity,” or “the only way to reduce cost is to outsource.” Here a common mistake is that they mix Muda with cost or profitability. More likely, they never observed the shop floor.


This arrow [B] represents thinking that there is a big waste in the process. There is a “gland-slam homerun” solution somewhere out there. That’s why few specialists focus on this process is essential. The batting average is low, but who cares, right? That’s how things are. Unfortunately, this is not the way TPS thinks.


This arrow [C] represents what Muda looks like for TPS. Muda is everywhere. TPS focuses on people development since few people can not discover and improve all over the plant. They need a group of people who can tackle these Muda.

As I picture the Muda on these arrows, I recalled a discussion. “Is it the reduction or elimination of Muda?” If we understand the points, the answer is elimination. But then, the arrow [C] is wrong.


The starting point of Muda is not always the endpoint of value-add work. Muda might exist one after another. For example, I tried to Kaizen material picking time. So I moved the rack closer. But that solved one Muda of “Depth.” But the Muda might have other issues, such as “Height” and “Width.” Sometimes, the “Angle” of the material presentations causes Muda. The material picking Muda consists of many “lines.” Identifying the lines and the root cause of it helps us implement good Kaizen.

By combining the value-add work, Muda, and the takt time, we form the standardized work. The standardized work helps us see the most critical Muda, which is over-production. There are two crucial characteristics of this area. First, Kaizen, eliminating the Muda is not part of the operator’s standardized work. This means that the operators are not responsible for eliminating the Muda. The takt time is calculated based on total available time divided by daily demand. Time is not allocated for Kaizen. Even if I make this explanation, some argue that use the downtimes to do Kaizen. But Kaizen relying on downtimes is an unreliable system (I’m not saying we shouldn’t do Kaizen during downtime). “Somehow, the operators will figure out when to do Kaizen” is not an acceptable answer. The only way to have Kaizen implemented is to have a separate “area” of responsibility. The responsibility of Kaizen belongs to the direct boss of the operator. Great managers know how to welcome the operators in Kaizen. It might start from a comment from an operator that the rack is too high. Great managers give credit of Kaizen to people. Sometimes, when the operator comes up with a great idea, the team leader will jump in the line while the operator works on the Kaizen. But the responsibility of the implementation belongs to the line management, not the operators.

Finally, I believe that a strong organization can standardize the presence & location of Muda throughout it. Logical reasoning uses deductive reasoning and inductive reasoning.

The structure of Muda should respect both reasoning. Strong organizations have an excellent capability to define Muda through deductive reasoning. Once they learn a way to eliminate Muda, this methodology is shared among organizations rapidly. This sharing is not done by just information flying around by mails. The leader learns first by visiting the shop floor. Then the leader gives coaching so that the direct reports get a hands-on experience to see and eliminate the Muda. The leader will challenge the direct reports to spread (Yokoten) through similar coaching methods within their responsibilities. The implementation happens through such cascaded learning organizations. The leaders continuously come to the shop floor to observe the broken telephone in the organizations if the shop floor does not meet the expectations.

Inductive reasoning is equally important. This reasoning starts with respecting the “1” problem. “Special case” is the idea-generating opportunity. Do not handle it as an “outlier” and ignore it. In the beginning, the “special case” should be challenged by the line. Yet, if the line does not develop a solution, the specialist is pulled to work together. The specialist will try all their knowledge, but they should get excited when those don’t work. They shouldn’t run away, which happens a lot. It’s the golden opportunity to learn something new. Even if it is a unique situation, breaking it down into structures will likely form a solution.

The leader needs to observe that both deductive & inductive Kaizen is happening in the organizations. My coach was never satisfied with just Kaizen implemented. He will ask why other processes in not learning from a Kaizen made. On the other hand, if everywhere implements the same kind of Kaizen, he will challenge the new one. He was looking for the balance between deductive & inductive Kaizen.

So when we go to the shop floor, don’t observe it vaguely. Be aware of the structure of Muda. Recognize the points-lines-areas-body of Muda. This should help to see more opportunities.

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