Since I posted about the “Net Work,” one more story on the same pie chart.
Japanese is a complicated language for many reasons. One reason why it is difficult is that we use three groups of symbols. Those three are Hiragana, Katakana and Kanji. And we could write the same word in all those symbols.
Toyota strategically utilizes the differences in these symbols to add depth and meaning to their communication.
For example, Kanban.
かんばん 【Kanban; Hiragana】; necessary Kanban.
カンバン 【Kanban; Katakana】; unnecessary Kanban.
看板【Kanban; Kanji】; Sign boards
It’s like a Zen dialogue to keep asking whether Kanban is necessary.
A similar usage is seen in “Muda (Waste).”
Taiichi Ohno’s “Toyota Production System” will use Katakana to describe Muda 【ムダ】. What we typically discuss as waste is always written in Katakana.
A fascinating history is that in the seventies, just about the time the “Toyota Production System” book was written, we started to see the use of Katakana to describe trash or waste 【ゴミ】. Before that, the Japanese used ごみ or 塵/芥. They started using the Katakana version to highlight the “trash/waste.” Nothing is wrong with using the Hiragana or Kanji. In a typical sentence, we will use mainly Kanji and Hiranaga. A Katanaka in the middle of a typical sentence will highlight the presence and grab awareness. It’s like using a different font. They started using Katakana in the seventies to hold the readers' attention. What is interesting is that today, we see the return of Hiragana 【ごみ】. This is because, as we shift towards a more recycling economy, what we thought trash might not be trash anymore. To create that need to recycle or reevaluate trash, we are reintroducing Hiragana.
This raises another question.
Is there a Hiragana Muda in TPS? 【むだ】
Yes. Hiragana Muda refers to the Muda that exists due to the mechanism of work. Katakana Muda refers to the seven types of waste and is “easy” to see. On the other hand, Hiragana Muda is more difficult to see. One example is work related to batch production. The large container's packing, transporting, and placing is categorized as Hiragana Muda. This means that layout issues are also Hiragana Muda. In other words, what Ohno has described as “Non-value added work” is Hiragana Muda. (For example, Nakano explains in such a way in this book.)
This creates a paradox.
Is this Non-value-added “work” or Muda (Waste)?
The difference becomes apparent when I make the pie chart. The second circle in the pie chart will look different. Which one is correct?
Or which one is the current condition?
Ohno wrote the following about “Non-Value-adding work:” “Properly speaking, we should think as Muda (Katakana), but it is necessary under current work conditions.”
He listed three examples;
Walk to pick up the components.
Unpacking packages from outside suppliers.
Operation of the push switches.
These works are necessary, but there should be a limit.
I have been to many places where the operator leaves the production area and walks to the warehouse to pick up the parts. It is necessary but over the limit. What is going to happen on the production side during the picking time? Production stops. What becomes the problem is that stopping becomes “necessary.” It becomes normal. It becomes normal for production workers to walk around during production hours. Now, it becomes hard to tell if someone is walking around to pick up the part or some other non-acceptable reason.
The same is true for packages. Some packages require enormous demolition work, especially those from abroad. It is necessary but over the limit. For example, one container took fifteen minutes to open and throw away the trash. The engineer justified by saying, “There are 1000 pieces in this container. It is less than a second of periodic work.” The math is correct but ignores the reality. For fifteen minutes, the operator has to do non-value-added work, not value-added work.
The same is true for the push switches. A touch whisker switch is necessary. But how many times must we touch the panel to start the machine?
Ohno is right not to call non-value-added work as Muda, but there should be a limit to what is allowed. Typically, such work is not recognized, or simple calculations hide the impact. The negative impact will be unstable quality and output, higher costs, and high inventory. It often leads to a poor working culture since the borderline between work and problems becomes unclear.
One improvement method is to remove such non-value-added work from the value-added production area. Excess walking to pick up components should be reassigned to a material handler. Opening complex containers will be done in warehouses. Such “improvement” will add a cost. But the benefit should save the production cost. Then, the identified added cost should be assigned to the “planners.” Whoever designed the layout should be responsible for the added cost due to a bad layout. Those responsible for the package should be responsible for increased unpacking costs. The higher operating costs of the machine must be assigned to the engineer. Bundling all “Non-Value-Added Work” and mixing inside the production cost is a suicide. Not all problems or wastes are production responsibility. “Hiragana” Muda is more challenging to see. Therefore, convert the Muda into cost and allocate to responsible functionalities.
Ohno did not want to refer to those works as “Hiragana” Muda because doing so would have been disrespectful to the people doing the work. He probably didn’t think of “Non-value-added work” as the responsibility of the shop floor to Kaizen. That doesn’t mean he left those works as is. There are plenty of stories of the fights Ohno had with the Engineers. Those were summoned to the shop floor and challenged about the thinking behind the poor design. I understand that the expectation is that engineers plan the details to the level we don’t have the Hiragana “Muda.” (Of course, it is very, very difficult, but that is the mentality.) Based on what happened at the Genba, the planning level goes higher daily so that the Genba can focus on the “Katakana” Muda.
“Non-value-added work” or “Hiragana” Muda. It’s actually the difference maker. We need lots of Kaizen in this area. It’s not a one-time classification. It’s an area that requires continuous questioning at the Genba. All of the linguistic gimmicks that TPS has been designed to create such reflection.
Last but not least, there is also “Kanji” Muda. It represents the Muda made by management. This is a vast topic that goes beyond this post.