Ishikawa Diagram: The Ultimate Guide to Using Ishikawa Diagrams

The success of a product in a majority of industries and businesses hinges on its quality and efficiency. But variation can degrade these two crucial qualities of the final product.

Once a client places an order, you should follow a predictable and standardized process through to delivery. This process usually means variation in the final product is eliminated or minimized, hence increasing the likelihood of meeting your client's specifications.

An Ishikawa diagram is a great tool to determine potential variables and mitigate failures and defects. It highlights where quality control issues might arise and helps decide which resources are required at particular instances.

What is an Ishikawa diagram?

An Ishikawa diagram is a fish-shaped diagram that shows the causes of a specific event. It is primarily used in product design or manufacturing to outline the different steps in a process. It allows managers to determine the vital issues they must address to achieve or avoid a particular outcome.

It can be used as a methodology for designing products that solve practical problems. Managers can use Ishikawa diagrams to prevent product quality defects by identifying the factors that can affect the final product.

Each reason or cause for imperfection is a source of variation. Ishikawa diagrams enable managers to classify these causes into significant categories to identify and group these sources of variation.

How to make an Ishikawa diagram

Ishikawa diagrams are sometimes referred to as fishbone diagrams, Fishikawa, herringbone diagrams, or cause and effect diagrams. This is because Ishikawa diagrams look like a fish skeleton. The ribs represent the causes of an event, and the skeleton's head indicates the outcome.

Here is how you can create an Ishikawa fishbone diagram in four easy steps.

#1. Identify and agree on the exact problem

The first step of creating an Ishikawa diagram involves identifying, agreeing, and writing down a problem statement. Figure out what the exact issue is, who's involved and when and where it occurs.

Write the problem statement in a box on the right-hand side, and then draw a horizontal line from your problem statement. The fish's head represents the problem statement, and the horizontal line resembles the fish's spine.

#2. Brainstorm the major categories of causes

By brainstorming with your team, decide how to categorize the significant factors causing the problem. These could be systems, materials, equipment, people, external forces, people, etc. Draw a line off the spine of the fish diagram for each cause and label each line at the very top.

#3. Identify possible causes

Identify the possible causes of the problem that may be behind each factor. Draw shorter lines off the bones of the fish diagram to help you visualize these potential causes. You may need to draw smaller sub-branch lines off a cause line if that particular cause is a bit more complex.

#4. Analyze the diagram

By the final step, you should have a fully fleshed fishbone diagram indicating all the possible causes of the problem statement. You can now investigate the issue further using investigations and surveys. You can also test to see which of these the main culprit is and help you solve the problem efficiently.

Ishikawa diagram software

Many Ishikawa diagram tools are available. Choosing one that provides Ishikawa diagram templates and examples will make creating fish diagrams a smooth sailing experience. MindManager is one of the best tools, and with a 30-day free trial, it can be a wise investment.

It can help your team find out the potential causes behind defects and failures that are presently occurring. Your team can then review these causes, identify the most likely root cause, and develop products that meet your client's specifications.


An Ishikawa diagram is one of the main tools used in root cause analysis. Sometimes called a fishbone or cause and effect diagram, an Ishikawa diagram is used by management to determine the reasons behind variations, defects, or failure within a specific process.

The cause and effect diagram tool combines brainstorming and mind mapping to discover the cause and effect relationship of an underlying design or production problem. It gives you insight into all probable causes of a problem instead of concentrating on the most apparent issues.

Software tools like MindManager help break down root causes that potentially contribute to a defect or effect. It also helps you uncover potential bottlenecks in your design or production processes and identify where they aren't working.

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