Kanban

Kanban: A Practical Guide

Key takeaways
* Kanban is a visual pull system originally developed at Toyota to support just-in-time production.
* It uses visual signals (cards, boards) to trigger replenishment and keep work flowing.
* Core goals: limit work-in-progress (WIP), expose bottlenecks, and continuously improve processes.
* Kanban applies to manufacturing, procurement, and knowledge-work; it can be physical or electronic.

What is Kanban?

Kanban (Japanese for “visual card”) is a signal-and-response system that controls inventory and workflow. When inventory or work at a station reaches a predefined trigger, a visual cue prompts replenishment or the next action. The system’s purpose is to maintain flow, avoid overproduction, and limit excess WIP.

Example: In a bagging line, a kanban card might be placed above the last 10 bags. When that card is reached, a runner brings more bags so the line doesn’t stop. Different stations may use different trigger points based on distance to supply.

Core practices

Kanban is defined by a small set of practical practices:

Visualize workflows
* Map the process step-by-step using boards, lists, and cards so everyone sees the current state.
* Swim lanes or columns represent stages or teams; cards represent individual work items.

Limit work in progress (WIP)
* Set explicit limits on how many items can be active in each stage.
* Limiting WIP reduces multitasking, shortens cycle times, and makes bottlenecks visible.

Manage flow
* Monitor how work moves and focus on reducing delays and variability.
* Use metrics like cycle time and throughput to understand performance.

Define policies explicitly
* Make entry/exit criteria, priorities, and handoffs clear so handovers are consistent and predictable.

Implement feedback loops
* Regularly review flow and outcomes, and make small, continuous improvements.
* Use standups, reviews, and metrics to adapt incrementally.

Improve collaboration
* Break work into small items so dependencies and handoffs are clear, encouraging cross-team communication and quick issue resolution.

Kanban board components

• Board: the overall workspace (can be team-, department-, or process-level).
• Lists/columns: stages of work (e.g., To Do, In Progress, Done, or specific production steps).
• Cards: individual work items with required details and acceptance criteria.

Boards can be physical (whiteboard + sticky notes) or digital (software tools), and are central to making process status visible.

Two-card systems and variants

In manufacturing kanban, it’s common to use specialized cards:
* P-kanban (production card): authorizes producing a fixed quantity.
* T-kanban (transportation card): authorizes moving containers to the next workstation.

These signals can be adjusted (trigger points, container sizes) to balance supply and demand and to prevent stockouts.

Electronic Kanban (e-kanban)

Digital kanban systems integrate with enterprise systems (ERP, inventory, transport) to provide real-time signaling across the supply chain. E-kanban preserves the visual signal while enabling automation (e.g., auto-generation of purchase orders, automated transport triggers), and is used by many modern manufacturers.

Scrum vs. Kanban

• Scrum: timeboxed sprints, fixed scope per sprint, roles like Scrum Master and Product Owner, measured by velocity. Changes are planned into sprint cycles.
• Kanban: continuous flow, no fixed sprint cadence, changes introduced incrementally, measured by cycle time, throughput, and WIP. More adaptive and flow-oriented.

Both can be complementary; Kanban focuses on flow and limiting WIP, Scrum on iterative delivery cadence.

Benefits

• Increased visibility and transparency of work.
• Reduced lead and cycle times, and lower carrying costs.
• Better predictability and early detection of problems.
• Greater responsiveness to change and improved customer service.
• Incremental, continuous improvement without large process overhauls.

Limitations and challenges

• Works best where processes and demand are reasonably stable and predictable.
• Requires organization-wide buy-in and discipline to update boards and respect WIP limits.
• If used without other supporting practices (e.g., JIT logistics), some benefits may be limited.
• Needs ongoing maintenance: stale or untracked cards defeat the system’s purpose.

Rules and purpose

Kanban’s practical rules center on:
* Visualizing work and policies,
* Limiting WIP,
* Managing flow and removing bottlenecks,
* Using feedback loops for continuous improvement,
* Ensuring cross-team communication and commitment.

The primary purpose is to save time, reduce waste and idle time, and surface constraints before they block the system.

Is Kanban Agile or Lean?

Kanban bridges both:
* Lean — by minimizing waste, excess inventory, and non-value activities.
* Agile — by enabling continuous delivery, adaptability, and pull-based flow.

Conclusion

Kanban is a simple, visual method to manage flow and inventory that scales from factory floors to knowledge work. When implemented with clear policies, WIP limits, and continuous feedback, it reveals constraints, shortens cycle times, and helps teams deliver value more predictably.