The purpose of Lean is to provide services or produce products with the minimum use of resources by eliminating waste. Everything that does not add value for the customer is waste — and Lean gives you the tools to find it and remove it.
Foundation
Lean thinking originated in manufacturing but now applies everywhere — offices, hospitals, logistics, financial services, and software. The core idea is simple: if a step does not add value for the customer, it is waste and should be eliminated or reduced.
Ford introduced the moving assembly line for the Model T in 1913, establishing foundational principles of flow, standardization, and waste reduction in manufacturing.
Ohno developed the Toyota Production System (TPS) — a comprehensive framework built on two pillars: Just-in-Time production and Jidoka (automation with a human touch). TPS became the blueprint for modern Lean thinking.
James Womack and Daniel Jones brought "lean production" (a term first used by researcher John Krafcik) to a global audience in The Machine That Changed the World (1990). Their book Lean Thinking (1996) defined the five Lean principles still used today.
Lean is now applied across discrete manufacturing, process industries, offices, healthcare, government, and software development — anywhere products are made or services delivered.
The Five Lean Principles
Womack and Jones defined five principles that form the backbone of every Lean transformation — from a single process improvement to an enterprise-wide program.
Specify value from the customer's perspective — what are they willing to pay for?
Identify all steps in the value stream and eliminate those that do not create value.
Make the remaining value-creating steps flow smoothly without interruption or waiting.
Let the customer pull value — produce only what is needed, when it is needed.
Pursue continuous improvement relentlessly — perfection is the goal, Kaizen is the journey.
TIMWOODS
Originally Toyota identified 7 wastes (Muda). An 8th — Non-Utilized Talent — was later added. The acronym TIMWOODS is a useful memory aid for all eight.
Unnecessary movement of materials, products, or information between locations.
Excess stock, WIP, or information held beyond what is immediately needed.
Unnecessary movement of people — reaching, walking, searching for tools or information.
Idle time when people, machines, or processes are waiting for the next step.
Producing more than the customer needs, or earlier than required — the worst waste.
Doing more work than the customer values — extra steps, approvals, or unnecessary features.
Errors, rework, scrap, or any output that does not meet customer requirements.
Failing to use the knowledge, creativity, and skills of your people — the 8th waste.
Lean Toolkit
Lean provides a rich toolkit for identifying and eliminating waste. These are the most widely used tools across manufacturing, healthcare, and service environments.
A visual tool to map all steps — value-adding and non-value-adding — in a process from raw material to customer. Used to identify waste and design the future state.
Sort, Set in Order, Shine, Standardize, Sustain. A foundation for visual management and the starting point for most Lean programs.
Small, incremental improvements made continuously by everyone in the organization. Kaizen events are structured improvement workshops typically lasting 3–5 days.
A visual scheduling system that controls work-in-progress and signals when to produce or replenish. Prevents overproduction and reduces inventory.
Documenting the current best method for performing a task — the foundation for training, process stability, and further improvement.
Maximizing equipment effectiveness through proactive and preventive maintenance, involving all employees to reduce unplanned downtime.
Designing processes and devices so that mistakes either cannot occur or are immediately detected — preventing defects at source.
Single-Minute Exchange of Die — techniques to reduce changeover or setup time, enabling smaller batch sizes and greater flexibility.
Making the status of processes, performance, and problems visible at a glance — using boards, signals, floor markings, and displays.
Reference Materials
Curated links from the site and trusted external sources to deepen your Lean knowledge.
The definitive reference for Lean terminology, tools, and principles from the world's leading Lean organization.
A practical walkthrough of Sort, Set in Order, Shine, Standardize, and Sustain.
A clear visual demonstration of how Lean flow outperforms traditional batch processing.
A real-world Lean factory tour showing visual management, 5S, and flow in practice.