What is the by-product of Kanban that we use in daily life today?
Answer: QR code.
The QR code, or “Quick Response code,” was invented in 1994 at Denso, a Toyota group company. It was part of their challenge to digitalize Kanban.
Barcodes have been used on Kanban since 1977. They speed up the scanning process, making it easier to collect information. As more suppliers were connected to the Kanban system, the need for digitalization increased, but there were challenges.
First, scanning with Kanban attached to the material was challenging. Although Kanban should be attached to the material (or the box), scanning can be difficult. Something easier to scan was needed.
Second, the barcode took up space when there was a need to keep other information more prominent. People need to see the info and confirm what it is picking up matches what they need to pick up.
Third, they wanted to increase more information.
Such contradicting conditions are good conditions for kaizen.
Fourth, since this is used in a production environment, the code must be strong enough to withstand dirt and uncleanness. In some cases, barcodes were damaged, making Kanban unreadable.
These challenges and the developer's hobby, Go, an East Asian board game in which players place black and white stones on a 19 X 19 grid, led to the creation of this QR code. Denso also sold barcode scanners, so it had the internal capability to support and develop such ideas.
The development history of QR codes is enjoyable and provides important lessons for implementing IT with TPS.
1️⃣ IT that follows the Kanban rules set by Ohno
Today, IT use is inevitable. But that doesn’t mean we can ignore Taiichi Ohno's Kanban rules. Those rules are:
Provides pick-up or transport information. The later process picks up the number of items indicated by the kanban from the earlier process.
Provides production information. The earlier process produces items in the quantity and sequence indicated by the kanban.
Prevents overproduction and excessive transport. No items are made or transported without a kanban.
Serves as a work order attached to goods. Always attach a kanban to the goods.
Prevents defective products by identifying the process of making the defects. Defective products are not sent on to the subsequent process. The result is 100% defect-free goods.
Reveals existing problems and maintains inventory control. Reducing the number of kanbans increases their sensitivity.
For some reason, as we use IT, we allow violations of some of the rules.
For example, in one place, a list of barcodes printed on paper was posted on the wall. Workers scanned these barcodes as they used the material. However, nothing was attached to the material anymore, and Kanban's visual sign capability was lost. Also, it was up to the person to scan as many as they wanted.
In another place, as soon as the IT was implemented, everybody learned how to increase the number of Kanban circulating in the system. It happened with a simple click in the system. As a result, it lost the function of highlighting problems and driving Kaizen. Kanban didn’t prevent overproduction anymore. Worse, the management discussed a plan to invest in a new warehouse.
2️⃣ Ease of use
The QR code is notable because it contains much information in a small space. What's even better is that it is easy to use, which is why it is popular today. This means that the developers at Denso cared about their workers' ease and time. How much time does it save? A few seconds. How much less rescanning is required? A few. How much easier? Few. Yet, these small things frustrate the workers. When these small things were accumulated as an entire company, they had a huge impact.
The discussion is NOT about whether or not to use a QR code. Do we care about those little times?
How often have we seen IT increase the work of a worker? There was a place where a worker had to scan and then correct wrong information in the system every time. Instead of fixing the root cause of the wrong database, people were forced to retype after each scan. There was a case where the worker had to walk to another place to scan. The walk was eliminated with a simple extension cable. The code reading was unstable in another place, and people had to double-check manually. According to the IT guy there, the scanner had a “personality” (This was before the AI era.). We just had to implement a poka-yoke to avoid poor reading. In another place, there was a Kanban with a massive IT company logo, and we could not print necessary information such as part name with decent size font. The nightmare goes on.
Denso developed something easy for workers to use. Because it was easy, and now everybody uses it. Of course, the technological development of smartphones contributed to the current spread of QR codes. Yet, the ease of QR codes has a definite advantage. No. I am NOT saying IT needs to develop something like a “QR code.” However, the ease of use should be considered as much as the data collection. The question should be, “How come my phone app is easier to use than this IT, which we use throughout the day?”
Source: Development of the QR-code (Two-dimensional Symbol),
and application to a production management system, Masahiro Nomura 2002