My name is Peter Herku. I help companies to become Lean and Six Sigma, which means to become more efficient and to produce better results and better quality in a shorter time.

Before I continue, if you want to become a lean and efficient company and you are responsible for a company or a part of the company, a department or team, then I have special offer at

The Belts

Clients come to me and ask whether they should start learning this Lean Six Sigma process improvement methodology at a Green belt level or a Yellow belt level or a Black belt level. These colours come from the Japanese martial arts as Lean has its origin in the Toyota company. This actually fits very well with me as I used to do karate. I have a Brown belt in Kyokushin, first kyu, if you know what it means. This is the last stage before the Black belt. I practised Karate for maybe eight or nine years and I enjoyed it very much because there’s a clear path what you have to learn, what you have to exercise and after every six months you will have an exam for you to show what you have learned. Based on the results you will get your next belt. With Lean Six Sigma it is a bit similar – there are clear requirements what you have to achieve and you start actually with Yellow belt. My clients are a bit frustrated because they get confused about information on the Internet. Of course Black belt is most attractive track to follow, but to become Black belt, you should become first Yellow belt and then get the Green belt. What’s the difference?

Yellow Belt

Yellow belt is the first level (some use White belt as well, but that really equals to nothing) where you get a basic understanding of the methods, so that you understand what phases you follow in process improvement and what methodologies or techniques you apply at each phase. If you have a basic understanding of that, because you followed the training or, preferably, you were a member of a Lean Six Sigma project team so you had really a real-life experience with the methodology – then you get a Yellow belt.  If you go to  I have a very special offer for you, which is actually a Yellow belt training. It’s called Green belt for beginners, but it is actually the first level, the Yellow belt level. I have a very special discount for now, it’s really ridiculous, so go to and take advantage of this nice offer. So Yellow belt is the basic understanding of the methodology.

Green Belt

The next step is Green belt where you have to apply the methodology in leading a real-life project. At least if you come to me and you would like to become Green belt, this is what I ask. Most companies have the same requirement: you have to apply the process improvement methodology in a real-life project. For example you would like to reduce the lead each time of your production process or sub-process. You will have to apply the method, measure the baseline to identify what’s the current performance or lead time, how many days or hours and, with your team, you have to identify customer requirements. Who are the customers of the process that we would like to speed up and what are their requirements. You look at the main customers and determine their requirements concerning the quality you should provide, about the time and timeliness and about the costs. You have to describe the current process, the current process flow within the first department that you try to improve and with your team you have to analyse the reasons why your lead time is too long. Then you prioritise those causes and identify and agree on certain countermeasures. After implementing those, you will measure the process again and see whether your lead time is reduced significantly or not. That’s very quickly the process you have to apply as a Green belt with your project team. If you achieve that you get your Green belt with. You can start with this at So Green belt is actually for those who have demonstrated in a real-life situation that they can apply the Lean Six Sigma method and deliver measurable improvement.

Black Belt

The next level is Black belt. To become a Black belt you need to implement improvement projects yourself (like a Green belt), but also train and coach a Green belt to apply the method. So Black belts are not only able to apply the method themselves but they are also able to teach others to do it. So that is the main difference with Green belt. In many other Lean or Six Sigma companies the Black belt training is a bit blown up with a lot of statistics and theoretical stuff.  I don’t believe in it. Based on my 12 years experience with Lean Six Sigma, there are only limited, very limited statistics required even for Black belts. Ignoring the statistics actually makes their work more efficient, because they can help many more green belts to successfully implement Lean Six Sigma. So if you want to start your journey and get your ranks, your belts in process improvement – start at:


Thank you!

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