Ohno's taxonomy of waste (muda) in production: (1) Transportation — unnecessary movement of materials, (2) Inventory — excess stock that ties up capital and hides problems, (3) Motion — unnecessary movement of people, (4) Waiting — idle time between process steps, (5) Over-production — making more than needed (Ohno considered this the worst waste, as it generates all the others), (6) Over-processing — doing more work than the customer requires, (7) Defects — producing items that require rework or scrap. This taxonomy became the analytical foundation of every lean methodology. taiichi-ohno developed it through decades of gemba observation at toyota-motor-corporation. An eighth waste — unused human talent — was later added by Western lean practitioners. The seven wastes are complemented by muri-and-mura (overburden and unevenness), which Ohno considered equally important but which received less attention in Western adaptations. Described in toyota-production-system-beyond-large-scale-production.