A Guide to the Yamazumi Chart

Learn about Yamazumi charts, how they work, and the different components of these charts.

business team looking at a yamazumi graph

Published 20 Jun 2022

What is Yamazumi?

The word Yamazumi means “to stack up,” and a Yamazumi chart is a stacked bar graph detailing the time it takes to accomplish specific tasks, providing a clear and easy way to visualize work processes. A Yamazumi chart assesses cycle times or how long it takes employees and machinery to finish different tasks.

The benefit of these charts is that managers visualize the workplace’s performance and efficiency. It also gives a clear assessment of what tasks take up too much time and where variations or waste stem from.

A Yamazumi is a bar graph consisting of an X and Y-axis. In the example below, each block represents a step in the process. The Y-axis shows the time it took to complete specific tasks or processes, while the X-axis represents different operators and workstations.

Yamazumi charts are color-coded to make it easier to interpret the graph and dissect the data. The chart allows you to view which areas of the process or what workstations require optimizations, making it much easier to meet goals.

Importance

A company’s main goal should always be increasing productivity and efficiency. This can make everyone’s job easier and increase the output of every area of operation. And the first step in increasing productivity is understanding what steps in the process take up the most time.

When you have an estimate of the optimal time it should take to finish a task and compare it with the actual time it takes to accomplish them in the workplace, it makes it easier to find the areas of improvement. This is the specific purpose of a Yamazumi chart and the reason why companies in different industries are utilizing it.

Generally, Yamazumi charts are used for time optimization and line balancing. With the chart, you get to directly compare the time it takes different operators to accomplish tasks, point out areas for optimization, and make small adjustments to help meet your goals.

Origins

The Yamazumi chart traces its roots back to Japan. The word literally means “to stack up.” It refers to how the graph stacks different tasks on top of each other for easy visualization of the entire process. Originally, these charts were used by car manufacturers in Japan, such as Toyota, who utilized these charts for line balancing and overall optimization.

However, while the chart originates in the manufacturing industry, it can be applied in many different ways. This chart works best for calculating and comparing machine time cycles, but you can also switch up the blocks with other workplace tasks and bring workplace optimization to the next level.

How It Works

One of the reasons Yamazumi charts are widely used in many industries is their simplicity. It doesn’t take too much practice and technical know-how to interpret a Yamazumi chart, which is why its applications aren’t just limited to manufacturing.

To start, a Yamazumi only contains an X and Y-axis. So, once you understand what each of the axes represents, understanding the message of the graph becomes much easier. The Y-axis shows the cycle time or time it takes to accomplish the task, while the X-axis shows the different tasks at hand and the operators in charge.

For example, one column in the graph could represent operator A while the other represents operator B performing the same process. You can plot each step in the process in the respective columns and stack them on top of each other. And by the end, you will clearly see what areas each operator performed better or worse.

You can plot a target cycle time for even more comprehensive data for each task. This gives you another reference point to determine how effective a specific operator is and how you can optimize the entire process.

Yamazumi can help eliminate wasted time, or “mura” as it’s called in Japanese, by giving managers a clear idea of how well different teams perform for certain tasks.

What’s in a Yamazumi Chart?

Understanding its elements is key to making an accurate and effective Yamazumi chart. And as mentioned earlier, these charts don’t have that many components, which allow them to convey simple and effective messages.

When creating a Yamazumi chart, all managers must know the processes the team needs to accomplish, each step in the process, and the different teams handling it. Additionally, it would be helpful to have a target or ideal time that you can use as a base comparison point for all the data.

You can plot the time in seconds, minutes, or hours depending on the needs of the company. And to make the graph even easier to understand, each block that is stacked on top of one another can be a different color. Managers can also assign colors to different operators according to their preferences.

The data in a Yamazumi chart are crucial to improving workplace efficiency and productivity. Companies can take that a step further by adopting modern tools for modern workplaces, such as iAuditor by SafetyCulture.

SafetyCulture staff writer

Leon Altomonte

Leon Altomonte is a content contributor for SafetyCulture. He got into content writing while taking up a language degree and has written copy for various web pages and blogs. Aside from working as a freelance writer, Leon is also a musician who spends most of his free time playing gigs and at the studio.

Leon Altomonte is a content contributor for SafetyCulture. He got into content writing while taking up a language degree and has written copy for various web pages and blogs. Aside from working as a freelance writer, Leon is also a musician who spends most of his free time playing gigs and at the studio.