Toyota and the Cord That Stops the Line

The story

Imagine working on a car assembly line where each car moves past you every minute or so. You notice a part doesn't fit right. Most factories in the past told workers to keep the line moving no matter what and let inspectors catch problems at the end. Toyota did something that sounded crazy: it let every worker stop the line.

The idea goes back to Sakichi Toyoda, who founded the group of companies that became Toyota. He invented automatic weaving looms. In 1896 he created a power loom that stopped by itself when a thread broke. That way, the machine didn't keep weaving bad cloth, and one person could watch many machines. Toyota calls this idea jidoka, often translated as "automation with a human touch." It means machines and people should stop as soon as something is wrong, so defects are not passed down the line.

Toyota's car business added a second big idea, called just-in-time. Kiichiro Toyoda, who founded Toyota Motor Corporation, pushed to make only what was needed, when it was needed, in the amount needed, so the factory would not pile up costly extra parts. After World War II, a production chief named Taiichi Ohno led the effort to build these ideas into a full system through the 1950s and 1960s. It became known as the Toyota Production System.

The andon cord is one of its best-known tools. Andon is a Japanese word for a paper lantern. In a Toyota factory, it is a signal board that lights up to show where help is needed. Toyota began using the andon system in 1950. On many lines, a cord runs along the length of the line. When a worker pulls it, a light and sound go off, and the board shows which workstation has a problem. A team leader rushes over. If the problem can be fixed within the time that the car would normally spend at that station, the line keeps moving. If not, the whole line stops until it is solved. Then the cord is pulled again to restart.

Why would a company let anyone stop a factory that costs a lot of money every minute? Because a defect that is fixed right away is cheap. A defect that is hidden inside a finished car, or found by a customer, is expensive and damages trust. Each pull also gives Toyota information. Teams study how often problems happen and what causes them, then improve the process so the problem doesn't come back. Toyota calls this steady, daily improvement kaizen.

The cord also sends a message about people. Toyota treats each worker as an expert on his or her own job and trusts them to protect quality. Pulling the cord is not seen as getting in trouble. It is seen as doing your job well.

Toyota's methods spread around the world, beginning in earnest with NUMMI, a factory in California that Toyota ran jointly with General Motors starting in 1984. Today, ideas from the Toyota Production System are used in hospitals, software companies and offices. Many of them have their own version of an andon cord: a clear, safe way for anyone to say, "Stop. Something's wrong here."