Why are so many quality terms in Japanese? Since the majority of quality management principles can be traced back to Japan’s automotive industry, it’s not entirely surprising. But what do these terms actually mean?

While many still debate the true origins of some of these Lean and Six Sigma terms, there's no question they play a major role from the plant floor on up to accounting.

If you’ve ever wondered about the translation and meaning behind these terms, here’s a list of eight terms underpinning common Lean principles.

1. Kaizen

While there’s no direct translation into English, Kaizen most closely translates to “change for the good.”

Manufacturers often come across this term when participating in a Lean event called a Kaizen Blitz. During a Kaizen event, a team of employees from different areas works on a week-long project to improve a specific process and reduce waste. This short-term project is followed by analysis and, often, a change in the product line or area.

2. Muri

In the 3 Ms of Lean, the first M, Muri, most closely translates to “overburden” or “over-exhaustion.”

The concept of Muri comes from employees or machines being pushed beyond a certain reasonable limit, to the point where that overburden actually slows down the process. Directly translated as “totally unreasonable”, it’s no wonder that Muri is traditionally the first thing that plant managers focus on reducing.

3. Mura

The second of the 3 Ms, Mura, roughly translates to or “inconsistency.” Mura can create big obstacles for quality, especially when it leads to variation in a standard process.

Multiple culprits can cause this unevenness, but it often results from fluctuations in customer demand. If customer demand unexpectedly increases, production can become overburdened (Muri). If demand unexpectedly decreases, it can create surplus or waste items that can’t be moved, called Muda (which we discuss below).

Manufacturers can reduce Mura by analyzing previous production and sales patterns to better predict customer demand and level out production schedules accordingly.

4. Muda

Translating to “waste” or “wasteful activity,” the third M of the 3 Ms in Lean aims to reduce unnecessary work and improve efficiency. If a plant can reduce Muda, it can increase productivity and profits while staying cost-efficient. In the Toyota Production System, the seven types of waste include:

● Transport

● Inventory

● Motion

● Waiting

● Overproduction

● Over-processing

● Defects

Not only are the 3 Ms important to reduce, the order in which you address them is also critical. That’s because by reducing Muri and Mura, you’re actively working toward eliminating Muda.

5. Poka-Yoke

Originating from the 1960s as part of the Toyota Production System, Poka-Yoke aims to create fail-safes and prevent human error where possible. It’s usually a mechanism or added step built into the process to alert the operator of a mistake that needs immediate corrective or preventive action.

An example of Poka-Yoke in everyday life is when you have to step on the brake or clutch pedal before starting your car. In this example, the extra process step prevents immediate forward acceleration, preventing potential accidents.

6. Kata

Kata literally means “the form and order of doing things.” Obsession with quality and executing processes in the correct and appropriate order is deeply rooted in Japanese culture.

Instead of rushing to fix a problem when you have little to no insight, Kata encourages thinking before doing. When plant managers coach Kata, they stress the importance of periodic observation, critical thinking, guidance and problem-solving skills. Through Kata, managers are able to focus on not only continuous improvement, but also innovation.

7. Gemba

The term Gemba means “the actual place,” and in manufacturing, the actual place of work typically refers to the shop or plant floor. Many manufacturers are already familiar with the concept of a Gemba Walk, where team members go to the plant floor and observe processes in action.

It’s important to note that the purpose of the Gemba walk isn’t to correct people or shame operators who aren’t following the process exactly. Gemba walks are meant to bring teams closer together and improve processes by identifying problems at the source.

8. Genchi Gembutsu

This Japanese phrase translates to “go and see for yourself,” also originating from the Toyota Production System. The idea behind Genchi Gembutsu is going beyond just looking at problems from afar and seeing the source of them yourself at the Gemba.

Managers often hear about a problem from someone else and accept that secondhand information as fact. Going to see the problem area with your own eyes inevitably helps improve problem-solving and insight into other potential problems.

While these terms represent common quality management practices, having a deeper understanding of their meanings can increase your effectiveness on the plant floor. Simply put, reducing waste and improving your bottom line requires understanding all the different forms of inefficiency and their source.