Creative Problem Solving Guide

Famous uses of the Ishikawa Fish Diagram 

In 1952, Kawasaki Iron Fukiai Works adopted the use of the Ishikawa Diagram to effect standardisation and control. It has since been adopted by a variety of manufacturers and their workplaces. 

Kansei ‘感性’ engineering, also known as emotional engineering, is the theory that emotions such as joy and excitement are as crucial as technical specifications. Kansei is a key design concept for Mazda, which led them to using Ishikawa’s Fish Diagram for their production of the Miata; MX-5, to decide upon key features of the car to make it an attractive car for their target audience. Through using the diagram, Mazda concurred that the sports car should be 3.98 metres in length and be a 2-seater to suit the needs of their clientele.  

1. First, outline the issue (effect) that you wish to analyse. Write this problem statement at the head of the "fish," which is usually on the right side of the diagram. 

2. Next, draw the backbone of the fish and add diagonal lines (fishbones) extending from it, leading to the main categories. For example, in the ‘Blurry Photo’ scenario; as shown above, the following categories have been used: 

• Equipment 
• Process 
• Environment 
• User 

If you are having trouble identifying the main categories for your problem, you can start with these common examples and adjust them based on the situation: 

• People (e.g., skills, training) 
• Methods (e.g., processes, procedures) 
• Machines (e.g., equipment, tools) 
• Materials (e.g., raw materials, supplies) 
• Environment (e.g., physical conditions, work culture) 
• Measurement (e.g., data collection, accuracy) 

3. Once the categories are established, begin brainstorming potential causes for the problem. To dig deeper into these causes, ask "why" multiple times to explore root causes. 

4. Finally, draw smaller lines branching off from the main fishbones to represent these primary causes. If necessary, you can add secondary lines for more detailed causes. The aim is to filter your results, so be cautious about an overflowing diagram which may lead to other problems. Ishikawa himself advises that diagrams should be adequately filled yet not too generalised in their approach as poorly produced cause and effect diagrams cause confusion. 

Once the causes have been identified, you can develop an action plan to address the initial issue. For example, in the case of the “Blurry Photo,” pinpointing the specific cause makes it easier to take targeted steps to eliminate the problem. 

After implementing the changes highlighted (such as replacing the lens, cleaning the lens, adjusting the environment), you should monitor the outcomes to ensure that the problem is resolved.  

Overall, the Ishikawa Diagram is mostly used for quality control within engineering, though can be used to approach elements of problem solving within different subjects too.