Takt time: where this strange expression comes from

In the TPS Only discussion group on LinkedIn, Casey Ng posted the following:

“It is quite clear that Takt is a foreign word (外来語) to both English and Japanese.
Its origin could come from German : Taktzeit.
Refer to “Walking Through Lean History” by Jim Womack ( President and founder of Lean Enterprise Institute:

‘By the late 1930s, the German aircraft industry had pioneered takt time as a way to synchronize aircraft final assembly in which airplane fuselages were moved ahead in unison throughout final assembly at a precise measure (takt) of time.’

Therefore, Toyota could have adopted the term and application from Mitsubishi who had technical link with the German in aircraft manufacturing.
But Toyota did breathe new life to the concept of takt by integrating it to the flow principle and inventory reduction of JIT. Therefore, any attempt to implement JIT without proper understanding of takt with Taiichi Ohno’s precise definition of takt time could fail.”

To which Bertrand Chauveau added:

“Takt is a German word

Casey, you are right. It is a German word used in music to describe the rhythm. Mitsubishi brought it back to Japan. Association of Japanese manufacturers deployed it throughout the industry. Thus Toyota adopted and adapted the concept to their production.”

And Frederick Stimson Harriman:

“Regarding the German origins of “takt,” I have never heard any of the Japanese consultants I worked with say where they thought the origin was, but a consultant from JIPM did say to me once that Shingo used the term, and so Bertrand’s explanation makes sense.”

Following are the results of my own research into the matter:

Takt is indeeed a German word, designating a bar on sheet music, but also an engine stroke as in Viertaktmotor (four-stroke engine), and the interval between trains on a line where they run regularly (picture by David J. Anderson), as shown below:

Lean implementers in Germany today, however, are just as confused about it as Americans, and I have heard some refer to Takt as the process time.

But how exactly did “Takt” migrate from Germany to Japan? I think the key reason the Japanese consultants Frederick worked with didn’t dwell on it is that it happened during World War II, and that Japan’s war time alliance with Nazi Germany is not a source of pride.

Digging further on the input from Casey and Bertrand, I found in Americanization and Its Limits a chapter by Katsuo Wada and Takao Shiba reporting that the military aircraft arm of Mitsubishi learned about the German “Takt system” from Junkers engineers in 1942, and had implemented it in the Nagoya works in fuselage assembly by 1943, under the name of zenshinshiki (前進式?). From a contemporary observer’s description, it looks very much like the pulse line system currently used for military aircraft at Boeing, with fuselage sections assembled at fixed stations and moved at a fixed interval — the Takt — to the next station.

This is to be contrasted with the moving assembly line concept used for aircraft also in World War II by Ford in Willow Run, MI, for the B24, and currently by Boeing for commercial aircraft. And it is not the same concept as takt-driven production today. But there are also accounts in German Aircraft of the Second World War of the German aircraft industry using moving lines for subassemblies during the war.

The Nagoya location of this Mitsubishi plant may not be coincidental to the transfer of the term to Toyota, which is still headquartered in that area. It may have been carried in the heads of unemployed military aircraft engineers joining Toyota after the war.

For the German part of the story, in German Aircraft of the Second World War, J.R. Smith and A.L. Kay, in their discussion of the Ju-88, explain “In August 1938, Ernst Udet laid down the Takt system of construction for all large state-owned firms such as Junkers and Arado…”

A Ju-88 flying in 1936

I also found the following picture of a Ju-88 assembly line in 1941, which suggests that the fuselages move sideways between operations rather than nose-to-tail:

Ju-88 Assembly Line in 1941

This is where the trail ends for now. Udet committed suicide in 1941, and was therefore not involved in the transfer to Mitsubishi. I have yet to find a detailed description of the Junkers “Taktsystem.”

4 comments on “Takt time: where this strange expression comes from

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