Does pulling the andon stop the line?

Not right away. On a fixed-position-stop line, pulling the cord signals for help while the job keeps moving. The team leader tries to fix the problem before the job reaches the fixed position (the end of the station). Only if it’s not resolved in time does the conveyor stop — and it stops at that fixed position, not wherever the car happens to be.

Why stop at a fixed position instead of immediately?

If the line stopped at a random spot, every other station would be interrupted mid-task, which itself causes errors like incorrect assembly. Stopping only at the boundary between stations keeps everyone else’s work whole, minimizes total stop time, and still guarantees the problem is dealt with before it moves on.

How does an operator know there’s a problem to call about?

Standardized work defines the exact sequence and time for each element, so the operator knows where they should be at every second of the cycle; floor markings show where the job should be. If they fall behind or spot a defect, the deviation is visible immediately — that’s what makes a timely call possible.

What is zone control?

Zone control means each process owns quality within its own “zone” and stops defects at the source, rather than relying on a final inspector. Operators are given the authority and the tools — error-proofing (poka-yoke) and andon — to catch problems where they occur, so nothing defective is passed to the next process. Automatic line stop is one method of zone control.

Who responds, and why does it matter so much?

A team leader responsible for a small team (often 5–7 operators). They need the availability to come at once and the skill to actually help — usually a highly experienced operator who has worked every station in the zone. If help is slow or feels like blame, operators stop pulling, and the whole early-warning system collapses.

Isn’t pulling the cord a lot a bad sign?

The opposite. Frequent andon pulls mean problems are surfacing early, while they’re small and cheap to fix. A line that never pulls is usually hiding defects, not avoiding them.

● Interactive Guide

Andon アンドン

Andon isn’t a light. It’s how a factory says “I need help” — and actually gets it, thousands of times a day. Follow one call from the standardized work that spots the problem to the response that solves it.

By Matt Savas · Kaizumi · interactive

The andon board hangs over the line — but the light is the smallest part of the system.

First — how do you even know there’s a problem?

It starts with standardized work

An operator can only call for help if they know something’s wrong — and that knowledge is engineered in. Every job has standardized work: a fixed sequence of elements, each with a known time. Add them up and you get the exact beat of the cycle — where you should be at every second. On the floor, painted zone marks make it visible. Scrub through one operator’s standardized work below.

Standardized Work Combination Table · Station 3 — Door trimcycle 52s · takt 55s

Where are we in the cycle?

This is the reference the operator works against — and the reason a call can be timely. Build your own → the SWCT tool · Work-element analysis guide →

The move · interactive

Pulling the cord starts a countdown — not a stop

Here’s the part everyone gets wrong: pulling andon doesn’t stop the line. The car keeps moving. You now have until it reaches the end of your span — the fixed-position stop — to fix the problem. Pull the cord, then get the team leader there in time.

Start of cycletime left in the spanFixed-position stop

A problem just appeared at station 3. Pull the andon to call for help — the car keeps moving while you do.

Try “team leader tied up” to feel why the response — not the cord — is the real system.

Why it works · zone control

Catch it in your zone — it never passes on

Andon is one tool of a bigger idea called zone control: instead of inspecting quality at the end, every process owns quality in its own zone and stops defects at the source. Same defect, two completely different systems:

✗ Traditional inspection

Quality checked at the end

A specialized inspector outside the process checks for defects — after they’re already built.
Defects travel downstream before anyone catches them.
Rework is expensive and the root cause is long gone.

✓ Lean zone control

Quality built in at the source

The operator owns quality in their zone, backed by error-proofing and andon.
Problems are caught the moment they appear, in the zone that made them.
Nothing defective is passed to the next process — the fifth rule of kanban.

🧭 Andon and poka-yoke are the two hands of zone control. Poka-yoke stops the error before it happens; andon calls for help the instant one slips through. Both are forms of jidoka — building in the ability to stop and fix, so a problem is never quietly passed along.

The part that isn’t the light

A cord is only worth pulling if help actually comes

The signal is the easy 5%. The system is the response. Pull a cord and no one comes — or the “help” feels like blame — and the operator never pulls again. So the response has hard requirements:

Immediate

Someone must come now, every time. One ignored call teaches the whole line to stop calling — and then problems hide instead of surfacing.

It has to feel like help

The responder solves the problem with you, not scrutinizes you. Fear kills andon faster than any defect.

Capacity + capability

The team leader must be free to respond and able to — ideally a master operator who has worked all 5–7 stations they cover. A designed role, not a spare manager.

A team leader striding to the station to help

Capacity: the team leader isn’t buried in other work — responding is the job.

A team leader helping the operator at the station

Capability: they’ve done every job in the zone, so the help is real.

This is why andon is a managerial system, not a light system. The hard part was never wiring the lamp — it was building an organization that always answers.

One more surprise

A healthy line pulls the cord constantly

1,000s

Andon is pulled thousands of times a day across a Toyota plant. A line that never pulls isn’t problem-free — it’s hiding problems. Every pull is the system surfacing a small issue while it’s still cheap to fix, before it becomes a defect the customer sees. Frequency is a sign of health, not failure.

Good to know

Frequently asked

Does pulling the andon stop the line?: Not right away. On a fixed-position-stop line, pulling the cord signals for help while the job keeps moving. The team leader tries to fix the problem before the job reaches the fixed position (the end of the station). Only if it’s not resolved in time does the conveyor stop — and it stops at that fixed position, not wherever the car happens to be.
Why stop at a fixed position instead of immediately?: If the line stopped at a random spot, every other station would be interrupted mid-task, which itself causes errors like incorrect assembly. Stopping only at the boundary between stations keeps everyone else’s work whole, minimizes total stop time, and still guarantees the problem is dealt with before it moves on.
How does an operator know there’s a problem to call about?: Standardized work defines the exact sequence and time for each element, so the operator knows where they should be at every second of the cycle; floor markings show where the job should be. If they fall behind or spot a defect, the deviation is visible immediately — that’s what makes a timely call possible.
What is zone control?: Zone control means each process owns quality within its own “zone” and stops defects at the source, rather than relying on a final inspector. Operators are given the authority and the tools — error-proofing (poka-yoke) and andon — to catch problems where they occur, so nothing defective is passed to the next process. Automatic line stop is one method of zone control.
Who responds, and why does it matter so much?: A team leader responsible for a small team (often 5–7 operators). They need the availability to come at once and the skill to actually help — usually a highly experienced operator who has worked every station in the zone. If help is slow or feels like blame, operators stop pulling, and the whole early-warning system collapses.
Isn’t pulling the cord a lot a bad sign?: The opposite. Frequent andon pulls mean problems are surfacing early, while they’re small and cheap to fix. A line that never pulls is usually hiding defects, not avoiding them.

Poka-yoke →Jidoka Standardized work (SWCT) →SWCT tool →The Five Whys →Hour-by-hour board →

Matthew Savas

Founder of Kaizumi, an AI-powered Lean training platform. More about Matthew →

Updated July 2026 · Station 3, its parts, and all figures are illustrative, created for teaching. The andon, fixed-position-stop, and zone-control principles follow the Toyota Production System.