What does yamazumi mean?

It is Japanese for 'stacking up'. The chart stacks each operator's work elements into a bar so the stacks can be compared with each other and with the takt time.

Where do the element times come from?

From a time study on the floor: several cycles per element, with the median or the lowest repeatable time. Times from the routing are usually wrong in both directions.

What is a good balance?

Every bar just below takt, with the last operator carrying the remainder so any spare capacity sits in one place. Then the waste blocks are the target: remove them and rebalance again.

Can LeanSuite measure the elements for us?

LeanSuite's Vision AI builds a line balancing study from a process video. The Lean Studio board is the hand-built version for a workshop, and the free line balancing calculator does the arithmetic.

Yamazumi or line balancing: are they the same?

Line balancing is the goal: distributing work so every station sits just under takt. The yamazumi chart is the picture you balance with. The calculator does the arithmetic; the chart shows the sequence and the waste.

How often should you redraw it?

Whenever takt changes, the product mix changes or a kaizen removes an element. A yamazumi from last year's demand is balancing a line that no longer exists.

Lean Studio board · Process & flow

Yamazumi Operator Balance board

In one sentence

A yamazumi chart is a stacked bar chart with one bar per operator, each bar built from that operator's work elements in seconds and drawn against a takt time line, so overload, waiting and imbalance between stations are visible at a glance.

A yamazumi chart stacks each operator's work elements into a bar and draws the takt time across all of them. Bars above the line are overloaded, bars well below it are waiting, and the colours show which elements are value-added, necessary or waste. The board is how a team rebalances a line by moving blocks between bars.

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When to use it

When to use the Yamazumi Operator Balance board

When one station on a line is always the bottleneck and the others wait on it.
After a takt time change, to see how many operators the new rate needs.
In a kaizen event on a cell, to move work between operators and remove the waste blocks.
To explain to a team why the line runs at the pace of its slowest station.

What is on the board

1
Takt time line
Customer demand turned into seconds per unit, drawn across the whole chart.
2
One bar per operator
Their work elements stacked in sequence, sized by seconds.
3
Element colours
Value-added, necessary non-value-added and waste, so the waste is visible.
4
Rebalance area
Space to the right to redraw the bars after moving elements.

Running it

How to run a Yamazumi Operator Balance session

1
Calculate takt first: available time per shift divided by customer demand per shift. Draw it as a line across the board before any bars.
2
Time each operator's work elements on the floor, several cycles each, with the team leader and an operator from the line in the room. Use the lowest repeatable time, not the average.
3
Build each bar from rectangles sized to the seconds, in the order the work is done. Colour value-added, necessary non-value-added and waste differently.
4
Read the chart: which bars are over takt, which are well under, how much of each is waste. Remove or shrink the waste blocks first.
5
Rebalance: drag elements between neighbouring operators until every bar sits just under takt, keeping the sequence workable. Put any spare in the last operator.
6
Write the new sequence per operator on a sticky, trial it for a shift and re-time it. Update the standard work sheet when it holds.
7
Good output: no bar over takt, waste blocks named and removed, and a new sequence per station that the operators helped write.

Worked example · sample data

Worked example

The sample chart has three operators against a takt of 60 seconds. Operator 1 stacks to 55 seconds: 18 loading, 24 fastening, 9 walking and 4 waiting. Operator 2 stacks to 68 seconds, over takt: 30 torquing, 22 inspecting and 16 seconds of rework. Operator 3 stacks to only 41: 14 labelling, 20 packing and 7 fetching boxes. The line runs at operator 2's pace, so every cycle is 8 seconds late while operator 3 waits 19. The team read the colours before moving anything: the rework at operator 2 and the box fetching at operator 3 are waste blocks. They agreed to stage boxes at station 3, then move inspection to operator 3, which brings operator 2 to 46 seconds and operator 3 to 56, with the rework still to be attacked at its source.

The board shown at the top of this page, read through. Invented data, not a customer.

Common mistakes

Using routing times instead of timing the floor. Standard times hide both the waste and the variation.
Balancing before removing waste. Moving a rework block from one operator to another balances nothing.
Ignoring walking and waiting because they are not 'work'. They are the amber and red blocks.
Balancing to average cycle time instead of takt.
Doing it without the operators. They know which elements can move and which cannot.

How it works in Lean Studio

1
Start from the Yamazumi Operator Balance template: the takt line and empty bars for each operator.
2
Add a rectangle per work element, sized to its seconds, and stack them on the operator's bar; colour by value-added, necessary or waste.
3
Drag elements between bars until every bar sits just under the takt line, then note the new sequence on a sticky per operator.
4
Save the finished board to My templates so the next team starts from your version.

Lean Studio boards are drawn with stickies, text, shapes (rectangle, rounded rectangle, ellipse, diamond), arrows and charts, and any board can carry the 15 data widgets, from a scorecard to a kanban. See all widgets and boards.

Also in LeanSuite

Where it goes next in LeanSuite

LeanSuite's Vision AI builds a line balancing study from a process video.

Vision AI builds the yamazumi from a video of the line: compare each station with takt, drag tasks between operators on screen, and save scenarios with the minutes and cost they save. The same video gives a time and motion study with each operator's time split into value-added, semi-value-added and non-value-added. AI Video Analysis
The rebalance becomes a Kaizen project with the labour saving recorded as hard or soft savings against plant targets. Kaizen & Projects
Which operators can take the moved elements is a skills question: the skills matrix shows who is qualified where and who to cross-train first. Competency Management

See Line Balancing

Open this board in LeanSuite

Yamazumi Operator Balance is one of the 30 ready-made boards in Lean Studio, LeanSuite's whiteboard. Try the interactive demo in your browser with sample data, or pilot LeanSuite on your own lines for 90 days, with the setup done by our team.

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