Application of Lean principles to software development has often been focused on identifying and eliminating waste (in Japanese: muda). However, Lean Thinking equally aims to remove overburden (Japanese: muri) and unnecessary variation (Japanese: mura). Together, these three (muda, muri and mura) are called "the three M's" in Lean. In his InfoQ article on The Lean Triad, Roman Pichler discussed the relationship between the three M's and argued that the elimination of overburden should be the first step for software development organizations in order to create a lean process.
So what's wrong with focusing, first and foremost, on seeing and eliminating waste? ... As long as people work crazy hours, and as long as projects and teams are overwhelmed by the amount of work, the removal of waste alone is ineffective. Waste is likely to creep back in unless we limit the amount of work to the capacity and capabilities of the organization.This is exactly what "The Planning Game" used in Scrum and XP does: limits committments to capacity, to give teams a real chance at improvement. Once they are allowed to establish the right process first by removing overburden, they can realistically be encouraged to tackle further improvements: eliminating waste and unnecessary variation relentlessly.