The Fishbone diagram (also called Ishikawa or cause-and-effect diagram) was invented by Kaoru Ishikawa for Kawasaki’s shipyards in the 1960s. It’s the RCA method of choice when you don’t yet know which cause category matters — give breadth, then let another method give depth.
Fishbone gives you breadth. The 5 Whys gives you depth. Run them in that order — Fishbone first to surface every plausible cause category, then 5 Whys on the branch that actually matters — and you’ll avoid the two most common RCA failures: drilling into the wrong root, and mapping causes you’ll never act on.
The four articles below cover the full workflow: the theory and history, worked examples across seven industries, a step-by-step creation guide, and free templates. Every diagram is real — pulled from actual consulting engagements, plant post-mortems, or incident reviews, not synthesised for SEO.
New to Fishbone? Start with the pillar guide on the right, then pick the example closest to your industry.
Read the guide for theory, examples for patterns, how-to for workflow, and template for your own session.
Origin with Kaoru Ishikawa, the 6M / 6P / 8P category frameworks, when to use it vs 5 Whys, and step-by-step construction.
ExamplesComplete diagrams from manufacturing, healthcare, software, restaurant, logistics, marketing, and HR — every 6M branch filled in.
How-toSeven-step workflow with HowTo schema: define effect, pick categories, brainstorm causes, validate, and drill into the vital few.
TemplateBlank worksheets for Excel, Google Sheets, and online use. When to pick each preset, plus a custom-category variant.
Manpower (people), Machines (equipment), Methods (process), Materials (inputs), Measurement (metrics and inspection), Mother Nature (environment). For service and knowledge work, the 6P variant is often used: People, Process, Policy, Place, Procedure, Technology.
Pick Fishbone when the cause is not yet obvious and you need to brainstorm categories. Pick 5 Whys when you already know roughly where the problem lives and want to trace one chain to its root. Many teams run Fishbone first, then 5 Whys on the highest-voted branch. See the full comparison.
Yes — 6M is a starting point, not a law. Add or rename categories that reflect your actual system. The template article covers custom-category workflow and the trap of too many branches.
Three to six. Fewer than three usually means the branch was irrelevant. More than six usually means the category was too broad and should be split. Watch for branches dominated by one person’s opinion — that’s a signal to widen the brainstorming pool.
Yes — our free Fishbone tool guides you through the 6M / 6P / custom categories and exports a PNG diagram. Your data stays in the browser. If you want a downloadable starting point instead, grab the free template.
Guided 6M / 6P / custom categories, live diagram preview, PNG export. No signup, no downloads, nothing leaves your browser.