Overview – Why It Matters
Step 8 marks the final stage of structured problem solving — and the true beginning of organizational learning.
After the countermeasures hold and stability is verified, the next responsibility is to reflect, recognize, and share.
Reflection is not remorse or finger-pointing; it is disciplined learning that begins after the doing is done.
As educational philosopher John Dewey wrote,
“We do not learn from experience — we learn from reflecting on experience.”
In Toyota, Hansei (reflection), Recognition, and Yokoten (horizontal sharing) are not symbolic rituals.
They are habits that turn individual problem solving into collective capability.
Reflection clarifies what was learned, what assumptions failed, and what must change to prevent similar issues elsewhere.
Recognition honors the people who contributed to the fix and the follow-through.
Yokoten ensures learning travels — so that one plant’s insight becomes another’s prevention.
In Toyota’s mature culture, these elements are mostly implicit—embedded in leader standard work, daily management, and PDCA rhythm.
For organizations without those reflexes, Step 8 must be explicit—a visible practice that ensures learning is preserved and shared.
The Evolution of Problem-Solving Frameworks in Toyota
Since the 1960s, Toyota’s problem-solving methods have evolved through multiple generations.
Different leaders emphasized different balances of technical rigor and learning reflection.
Across decades one can find 5-, 6-, 7-, 8-, and even 12-plus-step frameworks in circulation.
- Early 1980s five-step version: Define the problem → Analyze causes → Set a goal → Implement countermeasures → Check results.
- QC-Circle frameworks: Extended 12–14 step models focused on participation and education.
- Seven-step versions: Common in Japan during the 1980s–1990s, adapted by plant or department.
- Current TBP and PPS: Formal eight-step structures standardized company-wide.
In today’s Toyota Business Practice (TBP) and Practical Problem Solving (PPS), the final step is Standardize successful processes — not “Reflect and Share Learning.”
That difference is cultural, not procedural.
In Toyota, reflection and sharing are assumed behaviors.
In less mature systems, however, they must be stated clearly to ensure learning becomes institutional rather than incidental.
A Story of True Reflection – The Hard-Water Lesson
One of the most memorable examples of reflection came from a serious failure on an induction-hardening line at the Toyota engine plant in Georgetown, Kentucky.
Repeated coil-touch faults and abnormal quench-depth variation disrupted production and caused extended downtime.
After four days of nonstop work — cleaning the cooling lines, removing scale, installing filters, and adding a local reverse-osmosis (RO) water system — the line restarted smoothly on Monday morning.
The immediate root cause was clear: calcium and mineral buildup in the cooling-water loop had restricted flow and altered quench characteristics.
Technically, the issue was solved.
But at the hansei-kai reflection meeting that followed, Plant Manager Russ Scaffede and Executive Coordinator Tsutomu “TK” Kano led a deeper review that exposed how the problem had been allowed to exist in the first place.
The reflection unfolded in three layers:
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Engineering Oversight
When the induction-hardening machine was transferred overseas, the engineering team did not account for local water hardness in Kentucky’s limestone-based supply.
The project specification contained no requirement for hardness testing or filtration.
In Japan, where most plants use naturally soft volcanic water, this issue had never arisen. -
Machine Tool Standards (MTS)
The Japanese MTS lacked any clause requiring water-quality verification for engine-plant machine tools.
Since domestic plants never faced the condition, the standard gap was invisible until the overseas context revealed it. -
Manufacturing and Paint-Shop Standards (TMR/TMS)
Other divisions did already address water purity — but in a different context.
The vehicle-plant paint shops, governed by TMR/TMS, maintained strict limits for water filtration, conductivity, and mineral content because contamination could ruin a paint finish.
Those standards were never yokoten-shared with the engine plants.
The hansei-kai concluded that the issue was not an operational failure but an organizational learning gap.
Water-quality management existed in one part of Toyota but had never been extended across all manufacturing domains.
Within weeks, Kano coordinated with Japan headquarters to revise both TMS (Toyota Manufacturing Standards) and MTS (Machine Tool Standards) to include water-quality verification for all induction-hardening systems globally.
The reflection meeting itself was a model of Toyota culture — no blame, no emotion, only methodical learning and cross-functional insight.
It produced a permanent fix not just for Georgetown but for every plant that would install similar machines in the future.
That is Hansei and Yokoten in their truest forms: reflection that prevents repetition and strengthens the system.
Closing Thought
Step 8 ensures that problem solving does not end at the fix but continues through learning.
When reflection, recognition, and yokoten are made explicit, improvement becomes self-renewing.
The lesson from the Georgetown case was not about water at all — it was about assumptions, standards, and organizational connectivity.
Reflection closes the PDCA loop by ensuring that every solved problem makes both the process and the people wiser than before.