Methods & toolsFishbone / Ishikawa Diagram

What is Fishbone diagram?

A fishbone diagram (Ishikawa diagram) is a cause-and-effect diagram that structures possible causes of a problem into categories — classically the 6 Ms: Man, Machine, Method, Material, Measurement and Milieu (environment).

The diagram is used in teams to brainstorm broadly before digging deep: first all plausible causes are gathered on the “bones”, then the most likely ones are prioritised for verification at the gemba — with data, not a show of hands.

Fishbone and 5 Whys complement each other: the fishbone opens up the breadth, 5 Whys drills into the depth on the selected causes.

Download the Fishbone template

Related concepts

5 Whys

5 Whys is a root-cause technique where you ask “why?” repeatedly — typically around five times — until you get from the symptom to the underlying cause that can be removed, so the problem doesn’t return.

Root cause analysis

Root cause analysis is a structured investigation that finds the underlying cause of a problem — the cause that, if removed, prevents recurrence. Symptom treatment removes the effect temporarily; root-cause treatment removes the problem permanently.

A3 problem solving

A3 is a structured problem-solving method where the entire analysis — background, current state, target, root cause, countermeasures and follow-up — is documented on a single A3 sheet. The format forces clarity: if the problem can’t be explained on one page, it isn’t understood.

From concept to practice

The methods only work when they are anchored in daily routines and leadership behaviour. The operations check shows in 4 minutes where your operations stand — and what the next step is.

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