Yamazumi charts

The Yamazumi chart – also known as the operator line balance chart – is a load chart that breaks down the individual work tasks in a process, detailing the time they take. Obviously, it’s used in lean six sigma to good effect. You can download my version of the chart here.

While there are lots of different ways to plot this data, often a stacked bar chart is used (especially in Excel), usually in combination with another chart to show the % Waste, VA and NVA. The point though, is to help you to identify Value Added activities (VA), Non-Value added Activities (NVA) and Waste activities, so that you can work on reducing NVA and Waste.

Having been asked to help a colleague with a lean dashboard I did some research on the subject and found some great examples online. One chart in particular by Adaptive Business Management Systems is particularly good having a stacked bar chart with a pie chart to show the 2 sets of data. You can download their version for your personal / commercial use.  It even comes loaded with vba to update the chart as needed.

excel yamazumi chart

There are even online versions, like this one by Lean Lab.

yamazumi chart

Personally though I’d prefer to have all my information in one chart, have it organized and show very simply where I need to concentrate. It took a bit of work, but I came up with this version, a stacked bar chart with the VA, NVA & Waste plotted on the secondary axis behind the individual tasks. Basically any task that falls within the red (Waste) or yellow (NVA) areas needs to be eliminated / reduced. I’ve put the task name and category in the data label to make it clearer, similar to the ABMS version above.

yamazumi chart new

From the chart it’s clear to see that process 3 is already streamlined, whereas processes 1, 5 and 6 need the most work.

You can download my sample workbook and chart here if you wish to use it. Let me know what you think! Obviously this is still in draft form.  I need to add vba to make it update automatically as new data is added and I’ll probably tweak the formatting further – remove the visible secondary axis for example, but overall I’m pleased with the results.

Hope it helps!

+Alesandra Blakeston

7 thoughts on “Yamazumi charts

  1. I definitely like your overlapping/stacked bar approach, Alessandra. It conveys everything in one chart that’s easy to grasp right away. One key point in making your chart: It’s critical to structure/sort the data in a way that sequences the tasks into VA/NVA/Waste order.

    The ABMS chart is interesting as well, but I think it can be dramatically improved by eliminating a lot of the extra “junk” on the chart. For example, there’s no need to have a legend for each and every pie chart; you can just create a standard legend once that applies to all of the pie charts. Likewise, the pie chart title isn’t necessary as it just replicates the stacked bar categories immediately above them. Also, removing the boxes around the pie charts and the stacked bar, lets the 2 pieces of data appear to be unified. All of this lets you dramatically increase readability and the size of each pie chart. Lastly, I’d want to simplify all of the colors in the stacked bar–as they say, when everything is highlighted (colored) nothing stands out.

    Thanks for the great examples and food for thought!

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