Ask Art & Guests
Gemba Coach
The most common questions about TPS, Toyota, and lean thinking — collected from emails, conferences, and workshops over the years. Hot topics, history, controversial items, and corrections to some of what the internet gets wrong.
"What is A-D-P in lean problem solving?"
What Is the A-D-P Countermeasure Hierarchy?
A-D-P stands for Administration, Detection, Prevention — a hierarchy for evaluating countermeasure strength introduced by Art Smalley in Four Types of Problems. It applies to operational countermeasures on the shop floor. Upstream in product development, Toyota uses mizen-boushi for pre-occurrence prevention.
"What does gemba mean?"
What Does Gemba Mean?
Gemba (現場, correctly romanized genba) means 'the actual place' — the physical location where work happens. It is ordinary Japanese, not a Toyota invention. Toyota made it a management principle: go to where the work happens to understand what is really going on.
"What is a gemba walk, who should do it, and what's its purpose?"
What Is a Gemba Walk?
'Gemba walk' is a Western lean term for a structured management visit to the production floor. Toyota does not use this term. What Toyota practices is genchi genbutsu — going to the actual place to observe the actual thing — which is problem-driven, not calendar-driven.
"What is genchi genbutsu and what does it mean?"
What Is Genchi Genbutsu?
Genchi genbutsu (現地現物) means 'actual place, actual thing.' It is the Toyota practice of going physically to where work happens and observing real conditions directly before making decisions. It belongs to a family of principles called san gen shugi — the three actuals.
"Is one-piece flow always better?"
Is One-Piece Flow Always Better?
Flow is always better than batch production or stagnation — that is foundational in TPS. But the question conflates flow with one-piece flow and one-piece flow with the whole of JIT. Flow (nagareka) is one principle alongside takt time, pull, and leveling. The real distinction is between one-piece flow (ideal state) and small-lot production (current-state reality).
"What does jidoka mean and who invented it?"
What Does Jidoka Mean and Who Invented It?
Jidoka (自働化) means automation with a human touch — machines that detect abnormalities and stop themselves. The concept traces to Toyoda Sakichi's automatic loom, but auto-stop mechanisms existed in textile machinery decades earlier. Toyota's contribution was elevating the mechanism into one of the two pillars of the Toyota Production System.
"What does a Lean Promotion Office do and how is it organized?"
What Does a Lean Promotion Office Do?
A lean promotion office (LPO) or kaizen promotion office (KPO) is a staff group supporting improvement across an organization. The concept was sold to Western companies in the 1990s as Toyota's model — but Toyota's OMCD did something fundamentally different. The history matters because it explains why so many promotion offices failed.
"What does FMDS stand for at Toyota?"
What Does FMDS Stand For at Toyota?
FMDS stands for Floor Management Development System. In Japanese it is nichijō kanri ban (日常管理板) — daily management board. It is a physical board that connects company policy to shop floor activities through layered KPIs. The 'D' matters most: the system develops the group leader's management capability.
"What does jishuken mean?"
What Does Jishuken Mean?
Jishuken (自主研) means 'voluntary self-study' at Toyota. The formal Jishu Kenkyukai was founded in October 1976 by Toyota's OMCD to develop TPS capability in its supplier base. It is a hands-on group study activity on the shop floor — not a kaizen event. The five-day workshop format later marketed in the West is a consultant adaptation, not the original.
"What is a quality control circle (QC circle)?"
What Is a Quality Control Circle?
A QC circle is a small group of frontline workers who voluntarily study problems, learn analytical methods, and make improvements in their own work area. The practice originated in Japan in 1962 through JUSE. Toyota had 4,800 registered QC circles for example in 2001. Circles are a vehicle for personal development and learning — not a quality management mechanism.
"Who defined the seven wastes of lean?"
Who Defined the Seven Wastes of Lean?
Taiichi Ohno is credited with the seven wastes, but he assembled them from existing Industrial Engineering sources — not invented from scratch. Five map to ASME process chart symbols from 1947, one reflects Toyota's emphasis on overproduction, and one fills a gap from time and motion study. The framework was never meant to be exhaustive.
"Why does kaizen fail?"
Why Does Kaizen Fail?
Most kaizen efforts fail because organizations never make the transition from running improvement events to building an operating and management system that sustains results daily. The deeper causes: no standardized work baseline, methodology without technical depth, and leadership disconnected from the genba.
"Is there a difference between mistake-proofing and error-proofing?"
What's the Difference Between Mistake-Proofing and Error-Proofing?
In lean practice the two terms are used interchangeably. The distinction that matters isn't the words — it's mental slips versus planning mistakes, and knowing which you are dealing with changes where you aim the countermeasure.
"What is mizen-boushi?"
What Is Mizen-Boushi?
Mizen-boushi means prevention before occurrence — anticipating a failure and preventing it before it ever happens, upstream in design and development. It is the opposite of reacting to a problem after the fact, and the upstream end of the prevention picture that poka-yoke sits inside.
"What is the difference between muda, mura, and muri?"
What Is the Difference Between Muda, Mura, and Muri?
Muda is waste, mura is unevenness, muri is overburden. Most explanations treat them as three separate categories. Inside Toyota they are treated as one connected system — mura creates muri, and both generate muda. Heijunka (leveling) is the countermeasure to all three.
"Is poka-yoke a lean tool, and what does it mean?"
Is Poka-Yoke a Lean Tool, and What Does It Mean?
Yes, poka-yoke is a lean tool — but it isn't a Toyota-only idea and wasn't invented by one person. The original term baka-yoke was used across Japanese industry; inside Toyota it is a form of jidoka. Shingo gets full credit for popularizing it in writing.
"What is a standardized work chart and how is it built?"
What Is a Standardized Work Chart and How Is It Built?
A Standardized Work Chart is the best known organization of human motion for a job based on current conditions — layout, walk path, sequence, standard WIP, and safety/quality checks against takt time. It is dynamic: it changes with takt time and with kaizen. It is NOT an SOP. It is the final form of a three-form analysis.
"What is standardized work, including its 3 forms and 3 elements?"
What Is Standardized Work, Including Its 3 Forms and 3 Elements?
Standardized work in the Toyota Production System rests on three elements — takt time, work sequence, and standard work-in-process — and is developed through three linked forms: the Process Capacity Sheet, the Standardized Work Combination Table, and the Standardized Work Chart.
"Is takt time a KPI / a lean tool, and what does it measure?"
Is Takt Time a KPI, and What Does It Measure?
Takt time is not a KPI. It is a design constraint — the pace you design the work to, derived from customer demand divided by available time. It is one of three elements of standardized work and a key piece of Just-in-Time production.
"What is the difference between the Toyota Production System and Lean?"
What Is the Difference Between the Toyota Production System and Lean?
TPS is Toyota's actual production system, developed inside the company over decades. Lean is a Western translation framework derived from selected observations of TPS. The translation has real value, but it is not the original — and mistaking the two has consequences.
"Does Toyota do value stream mapping?"
Does Toyota Do Value Stream Mapping?
Toyota does not draw LEI-style value stream maps or train them internally. But Toyota developed MIFA — the practice value stream mapping is based on — and a small number of specialists still use it.
"Does Toyota practice Toyota Kata?"
Does Toyota Practice Toyota Kata?
Toyota does not use the term Toyota Kata. The word kata maps to many different kanji in Japanese — none exactly match what the book describes. Toyota's actual practices for coaching and improvement are Toyota Leadership Training Methods, FMDS, and 3 Pillar Activity.
"Does Toyota do TPM or measure OEE?"
Does Toyota Use TPM or Measure OEE?
Toyota has never had an official TPM program or used OEE as a metric. But in machine-intensive environments, Toyota built up many of the same elements independently through its own system.
"Does everyone in Toyota create A3 reports for problem solving?"
Does Everyone in Toyota Write A3 Reports for Problem Solving?
Everyone in Toyota learns to write A3 reports, but most problems are solved verbally or with simpler task-specific forms. A3 reports are triggered by harder, recurring, or safety-critical problems.
"Is it 4S or 5S inside Toyota?"
Is It 4S or 5S Inside Toyota?
Toyota used 4S as the company standard for decades. The fifth S was added outside Japan to compensate for cultural differences. The worldwide standard is now 5S, but the original inside Toyota was 4S.
"Is it Gemba or Genba?"
Is It Gemba or Genba?
The correct romanization is Genba (現場). But Gemba won in the English-speaking lean world after Jim Womack's Gemba Walks. The Japanese language has no single consonant M — the 'n' just sounds like 'm' to American ears.
"What is the difference between value stream mapping and process mapping?"
Value Stream Mapping vs Process Mapping
Process mapping records activities as a flowchart. Value stream mapping diagrams material and information flows from order to delivery. Toyota modified process mapping into MIFA; LEI renamed it value stream mapping.