Gemba is Japanese term meaning the place where the truth can be found. It is only at the gemba that you learn "unknown unknowns".

In quality management, gemba means the manufacturing floor and the idea is that if a problem occurs, the engineers must go there to understand the full impact of the problem using all their senses to gather and process data. Unlike focus groups and surveys, gemba visits are not scripted or bound by what we want to ask.

Glenn Mazur introduced this term in the Quality Function Deployment (QFD) (a quality system for new products where manufacturing has not begun) to mean the customer's place of business or lifestyle. The idea is that to be customer-driven, you must go to the customer's gemba to understand his problems and opportunities, using all your senses to gather and process data.

Japanese detectives call the crime scene a gemba.