Lean in a nutshell

The lean body of knowledge in a neat little package

Chris Lennon
6 min readMar 5, 2020

Updated: 22 October 2020

Photo by Heather Gill on Unsplash

There is so much ‘good stuff’ out there in the world of business improvement, it can be a bit overwhelming. In this post I want to talk about Lean, a word often bandied about and often misunderstood. Lets bring some real clarity to what ‘Lean’ actually is.


If all you are looking for is an answer to the question “what is Lean” here you go 😊

Lean is way of thinking and set of practices born in the post WWII Japanese automobile manufacturing industry. The primary focus of Lean is the identification of value streams, and the systematic elimination of waste within those value streams to produce an even flow of value with quality to the customer. The father of Lean is Taiichi Ohno who developed, over decades, the Toyota Production System. The system, which the author describes as a “production and management system” is outlined in his book ‘Toyota Production System’ first published in Japanese in 1978 and translated into English in 1988. Because of these origins Lean is sometimes known as ‘Lean Manufacturing’

Origins of Lean

To understand something, I always find that going back in time to its birth is a good place to start. Ideas build on other ideas, which build on other ideas and so on. So in a way its never really possible to find the true origin of an idea. There is nothing new under the sun as the Bible has it. Having said that, when tracing the path of an idea, some places are more logical to start with than others. So lets start in Detroit, USA in the early 1900’s

Henry Ford and the mass production system

Henry Ford started making cars the way most things were made at the time, one at a time. A car was assembled, from the ground up. The game-changing innovation Ford and his team developed was to bring the car to the parts, rather than bringing the parts to the car.

Photo: https://drivetribe.com/p/did-henry-ford-invent-the-assembly-UiuQ8uljSt-zGWiy7Yal-A?iid=M7l9FUN_QhK0b9wSF8H8HA

Taiichi Ohno

Ohno, Taiichi. Toyota Production System. Taylor and Francis.

Motivating formation of the Toyota Production System was the economically driven need to produce cars in small batch sizes to meet many different market niches. Henry Ford initially offered a single model, the model T and famously offered his customers a choice of “any color so long as its black”. In contrast Toyota needed to meet the needs of an increasingly sophisticated car buying population who wanted choice in their automobiles. From Ohno’s book:

The number of varieties reaches thousands just by considering the combinations of car size and style, body type, engine size, and transmission method. If we include colors and combinations of various options, we will rarely see completely identical cars.

Ohno, Taiichi. Toyota Production System (p. 37). Taylor and Francis.

This then was the challenge, how to get the efficiencies of single-batch production with the flexibility the customers were demanding. Taiichi Ohno developed the Toyota Production System over decades to meet this challenge.

Underpinning Toyota’s journey to the Toyota Production System is the concept of removing waste and waste elimination is the ‘poster child’ of Lean today. A diagram at the start of Ohno’s book illustrates this concept

Image from Ohno, Taiichi. Toyota Production System. Taylor and Francis.

As a point of interest Ohno does not use the word “Lean” in his book at all, rather that name was coined some decades later in the book ‘The machine that changed the world’ (pub. 1990) , which helped propel Lean concepts beyond the automobile industry and into many other industries such as Information Technology.

Summarising a large body of knowledge into a few bullet points is always going to involve an element of subjectivity. Here is my take on the original core concepts of Lean, as drawn from Taiichi Ohno’s work:

  • Know your value streams
  • Eliminate Waste
  • Produce Just In Time
  • Build quality in
  • Use Visual Management
  • Use a Kanban system to pull work from earlier stations
  • Manage Flow
  • Practice Kaizen (Continuous Improvement)

In terms of ‘eliminate waste’ Ohno identifies 7 wastes:

  • Waste of overproduction
  • Waste of time on hand (waiting)
  • Waste in transportation
  • Waste of processing itself (un-needed processes, excess processing)
  • Waste of stock on hand (inventory)
  • Waste of movement
  • Waste of making defective products

Ohno, Taiichi. Toyota Production System (pp. 19–20). Taylor and Francis.

Theory of Constraints

The Theory of Constraints (TOC) is outlined by Eli Goldratt in his book ‘The Goal’ (first pub. 1984) which tells the fictional story of manufacturing plant manager Alex Rogo as he battles to turn around the struggling operation he manages. Guided by words of wisdom from enigmatic physicist Jonah, Alex learns a number of lessons in the field of business and manufacturing management. There are a number of powerful concepts in this work; perhaps the most significant assertion of Theory of Constraints is that within a system there is always a constraint — sometimes called a bottleneck — and the first, and in some ways the only task we have as managers of a system is to focus on the constraint.

In terms of how we do this, Goldratt outlines what he terms a ‘Process Of Ongoing Improvement’ (POOGI) with five focusing steps:

1. Identify the system’s constraint (the factor most responsible for the system’s failure to achieve higher performance).

2. Decide how to exploit the system’s constraint (since the constraint is determining the performance of the system, make sure the constraining process is working at full capacity).

3. Subordinate everything else to the previous decision (effort should be directed only to exploiting and elevating the chief constraint, do not focus on other constrains that are not the bottleneck).

4. Elevate the system’s constraint (find ways to increase capacity at the constraint and/or make process changes to reduce pressure on the constraint).

5. Repeat (prevent inertia from becoming the constraint).

Lean for software development

More recently Mary and Tom Poppendieck in their book “Lean Software Development” (pub 2003) draw out seven lean principles and apply them to software development:

  • Eliminate Waste
  • Amplify Learning
  • Decide as late as possible
  • Delivery as fast as possible
  • Empower the team
  • Build integrity in
  • See the whole

As you can see, these are not necessarily the original principles espoused by Taiichi Ohno, although you could say that they are broadly speaking in line with Ohno’s management philosophies. And even more broadly speaking, that they are in line with the Lean body of knowledge.

More Leans

I am going to wrap up this blog without going into Lean Startup or Lean six sigma. Lean is a word and a concept that is sometimes used to give more ‘grunt’ to concepts. Nothing wrong with this, but as business systems professionals we need to be clear when we use this word in a business context.

My challenge to leave you with: when you next hear someone use the word ‘Lean’ ask the question: “when you say ‘Lean’ are you referring to Lean as Taiichi Ohno described it in his 1978 book ‘Toyota Production System’?” If you can avoid being seen as a smart-@ss, the hesitation and uncertainty that will meet this question could be the start of a real conversation rather than just an exchange of buzz words.



Chris Lennon

Agile coach. Ways of Working researcher. I live in beautiful New Zealand and work for Spark. I am also the founder of a start up — voyzu.com. Views are my own.