Those familiar with lean manufacturing have likely heard the word muda many times. Muda is the Japanese word for waste and is the enemy of us all whether we know it or not.

Strangely enough muda is not the only enemy of a lean system. There are two more, less popular (at least in Western companies), M’s we must also be aware of – namely mura and muri.

Mura

Mura in its simplest form means “unevenness.” For example, mura results when your operators are told to work like crazy early in the morning only to stand around and do nothing late in the day. Heijunka may be the answer to this problem but let us save that for another blog.

Muri

Muri means to “overburden” equipment or operators. For example, if your entertainment center is only meant to hold 200 pounds and you place your new 425 pound super duper HD Ready TV on it we have muri. We also have other issues like a very real safety concern!

Leads to Muda

So the next time someone drops the word “muda” in their attempt to show you how much they know about lean you may be able to educate them on the other two M’s that are just as important as the infamous muda. Of course you should be humble and polite during this education process.

For the overachievers out there who can tell me which of the three M’s (muda, mura, muri) are visible in the donkey picture above?