Is the Lean Organisation a complex system?

The Lean Organisation enjoys a tremendous success. It was first developed within Toyota Motor Corporation in the Automotive Industry, but was then adopted by many organisations in all fields of human activities. A deeper observation of this success displays behaviours of complex systems: a high number of agents interact with each other, using basic routines for which they have been coached systematically, creating a much better result than each individual could have reached by themselves (emerging behaviour).
We model two significant processes of Lean: Hoshin Kanri (for management of the organisation objectives) and Nemawashi (consensus building). The simulations performed based on these models show qualitative as well as quantitative evidence for emerging behaviours of the Lean organisation. They also allow to demonstrate the existence of several success factors for the Lean organisation: proficiency of the agents, readiness of the management to accept emergent proposals, and strong requirement for rigour in the execution of the decision process.