Most Lean practitioners that I have met have little idea as to what is Mura only really being aware of Muda or the seven wastes. Within the Toyota Production system however, which spawned what we now call lean, they concentrate on three main areas of waste; Mura (unevenness), Muri (overburden) and Muda (non value adding activities).
While Muda is very much something that everyone can identify with and be happy tackling most companies and practitioners fail to identify the other two categories, Mura and Muri, which are often the main causes of the Muda in the first place.
Uneven customer demand
Mura is unevenness or inconsistency; it is the uneven demand levels that we often see in our companies from day to day or even month to month. We fail to smooth out production and try to rush as fast as we can from one large batch to the next with little thought as to what the customers actually need.