Jidoka means "automation with a human touch" (sometimes called "autonomation"). In a manufacturing facility, this might mean a group of machines perform a task automatically, but one person oversees them. This is beneficial because rather than having one machine operated by one operator, people can be freed up for other tasks.
Often, machines are built with the capacity to identify problems and stop when something goes wrong. This concept originated with an automatic loom invented by Sakichi Toyoda in the late 19th century. This machine would stop when a thread broke. When a machine like this stops, a person can step in and work to find the root cause of the problem. Jidoka is one of the pillars of the Toyota Production System. It is important because it ensures products are made with high levels of quality because defects are automatically detected throughout the process. This is preferable to trying to look for quality issues once a product is complete because it is more difficult to go back and find a problem than to identify it right away when it occurs. When problems are identified immediately, it's easier to find the root cause.