The 6 Rules for Effective Kanban

Toyota Production Systems saw the need for implementation of Kanban within their production systems to create an optimum flow of work and reduce waste in the production line. Over the years, their Kanban application went through improvements and eventually the Six Rules helped improve their production capability through the use of Kanban. The Six Rules for Effective Kanban defined by Toyota are:

1. Never pass on defective products.
2. Take only what is needed.
3. Produce the exact quantity required.
4. Level the production.
5. Fine-tune production.
6. Stabilize and rationalize the process.

Toyota Production System defined these 6 rules for themselves, so they could implement Kanban effectively.

In this blog we will try to understand the rules and, if and how they apply to knowledge work.

Here are the Six Rules for Effective Kanban:

1. Never pass on defective products:

For a manufacturing production line, this rule seems pretty straight forward. As the statement  efines itself, no defective product should be passed to downstream processes. This would clearly ensure the desired quality of product going out to customers. Now when we look at this rule in the context of knowledge work, it continues to be an extremely important rule. Take for instance, software development workflow, defects can leak at any stage of the workflow, be it requirements gathering or design or coding, so this rule is basically asking to ensure quality and governance at each stage of the workflow. For knowledge work Kanban systems, explicit policies for each work stage should ensure that the work product meets the desired quality.

2. Take only what is needed:

This rule means that downstream processes should pull only what they need. In the manufacturing world, this would clearly mean much lesser wastage, no overproduction or over inventory.  Now let us understand this in the context of knowledge work. For knowledge work, this means that pull of product or features should happen only and only when there is customer’s demand. This rule is also perfectly in alignment with the rule of “deferring commitment until the last moment”, which means that teams must commit to develop a feature or product, only and only when a customer is ready to commit to take the product.

3. Produce the exact quantity required:

For manufacturing, this clearly means that manufacture only the amount the customer needs or customer is ready to pay for. Producing anything more would amount to creating waste. For knowledge work, this translates into producing Minimum Viable Product, a product with only the features that customers are ready to pay for. Anything else would add no value.

4. Level the production:

In the manufacturing production system, leveling production means adjusting the production capacity of all the processes to the slowest process. But why do we really need to level the production system to the slowest process in the system? This is because any production system is only as fast as the slowest process in the system. When you level the system, you are ensuring optimum use of capacity available across the system and it also offers the opportunity to reduce any delay and improve the system’s overall capability. In knowledge work, this translates into identifying bottlenecks, optimizing work stages that run into bottlenecks and then leveling of capacity/wip limits, so as to maintain a continuous flow of work.

5. Fine-tune Production:

This rule means that you track your key metrics and measures and change your policies across the production system, so you improve your system’s capability. In knowledge work, this translates into tracking the lead time, cumulative flow diagrams, throughput and other metrics and continuously working towards fine tuning policies across the system to improve its capability and flow by removing bottlenecks and addressing the variability and delays.

6. Stabilize and rationalize the process:

Stabilize and rationalize as the statement suggests, refers to making incremental changes over time and focusing on stabilizing the processes, such that there is balance in capability and demand and the system becomes predictable through the process.

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Reference to the 6 Kanban rules at Toyota

https://mag.toyota.co.uk/kanban-toyota-production-system/