Why yokoten matters
Most operations solve the same problem many times. A line fixes a jam, a sister line has the same jam a month later, a second site a year later. Each solves it from scratch. Yokoten closes that gap: once a countermeasure is verified, it is shared with everyone who could use it, and they adopt or adapt it.
What yokoten is not
It is not copy-and-paste. The receiving team looks at the countermeasure, understands why it worked, and adapts it to their conditions. Toyota describes it as sharing the thinking, not just the solution. A standard imposed without that understanding tends to be ignored.
How to practise yokoten
- Verify the fix first. Only share countermeasures whose effect has been confirmed against the measure.
- Capture the why. Record the problem, the root cause and why the countermeasure addresses it, usually on the A3.
- Identify where else it applies. Similar equipment, processes, products or hazards, across lines and sites.
- Share with the people who would use it in their tier meeting or improvement review, not only by email.
- Track adoption. Each receiving area confirms it has reviewed the item and either adopted, adapted or explained why it does not apply.
- Check the result where it was adopted.
Yokoten and daily management
Yokoten works best as a routine. When a Tier 2 or Tier 3 meeting closes a significant A3, the next question is "where else does this apply?", and the answer becomes actions for the other areas. Safety is the clearest case: a hazard found on one line should trigger a check on every similar line that week.
Common failures
- Sharing fixes before they are verified.
- Sending a document and assuming it was read.
- No record of who adopted what, so nobody knows whether the learning spread.