The 5 key principles of Lean, as explained originally by the MIT group ( Jim Womack et al ) after 5 years and $5 million in research of the Toyota Production System. They are of course 1. Identify Value to your customer of your service or product 2. Understand your value-stream 3. Implement ‘pull’ or JIT in your value stream 4. Create Flow in your value-stream 5. Strive for perfection in your processes with continuous improvement. Students of Lean Six Sigma are required to understand these 5 key Lean principles and the methods, tools and techniques required to achieve them.