Dna Toyota

Decoding the DNA of the
Toyota Production System
by Steven Spear and H. Kent Bowen

Reprint 99509

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art work by a my ning

The
Toyota
story has
been intensively
researched and
painstakingly
documented,
yet what really
happens
inside the
company
remains a
mystery.
Here’s new
insight into
the unspoken
rules that
give Toyota
its competitive
edge.

Decoding theDNA of the
Toyota
Production
System
by Steven Spear and H. Kent Bowen

T

h e Toyo t a P ro d u c t i o n S y s t e m h a s
long been hailed as the source of Toyota’s
outstanding performance as a manufacturer.
The system’s distinctive practices –its kanban cards
and quality circles, for instance – have been widely
introduced elsewhere. Indeed, following their own
internal efforts tobenchmark the world’s best manufacturing companies, GM, Ford, and Chrysler have
independently created major initiatives to develop
Toyota-like production systems. Companies that
have tried to adopt the system can be found in fields
as diverse as aerospace, consumer products, metals
processing, and industrial products.
What’s curious is that few manufacturers have
managed to imitate Toyotasuccessfully – even
though the company has been extraordinarily open
about its practices. Hundreds of thousands of executives from thousands of businesses have toured
Toyota’s plants in Japan and the United States.
Frustrated by their inability to replicate Toyota’s
performance, many visitors assume that the secret
of Toyota’s success must lie in its cultural roots.
But that’s just not thecase. Other Japanese companies, such as Nissan and Honda, have fallen short
of Toyota’s standards, and Toyota has successfully
introduced its production system all around the
world, including in North America, where the company is this year building over a million cars, minivans, and light trucks.
So why has it been so difficult to decode the Toyota Production System? The answer, we believe, isthat observers confuse the tools and practices they
see on their plant visits with the system itself. That
makes it impossible for them to resolve an apparent
paradox of the system – namely, that activities, connections, and production flows in a Toyota factory
are rigidly scripted, yet at the same time Toyota’s
operations are enormously flexible and adaptable.
Activities and processes areconstantly being challenged and pushed to a higher level of performance,
enabling the company to continually innovate and
improve.
To understand Toyota’s success, you have to unravel the paradox – you have to see that the rigid
specification is the very thing that makes the flexibility and creativity possible. That’s what we came
to realize after an extensive, four-year study of the
ToyotaProduction System in which we examined
the inner workings of more than 40 plants in the
United States, Europe, and Japan, some operating
according to the system, some not. We studied both
process and discrete manufacturers whose products
ranged from prefabricated housing, auto parts and
final auto assembly, cell phones, and computer
printers to injection-molded plastics and aluminum

Copyright ©1999 by the President and Fellows of Harvard College. All rights reserved.

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d e c o d i n g t h e d n a o f t h e t oyo t a p ro d u c t i o n s y s t e m

extrusions. We studied not only routine production
work but also service functions like equipment
maintenance, workers’ training and supervision,
logistics and materials handling, and process design
and redesign.
We found that,for outsiders, the key is to understand that the Toyota Production System creates a
community of scientists. Whenever Toyota defines
a specification, it is establishing sets of hypotheses
that can then be tested. In other words, it is following the scientific method. To make any changes,
Toyota uses a rigorous problem-solving process
that requires a detailed assessment of the current
state of...