The founder of Ko-ken Tool Co. Ltd. was Mr. Soichiro Yamashita (1889-1973)

• Founded Ko-ken Tool Co. Ltd in 1946 at the age of 57.

• He had lived in U.S.A. for 18 years

•Worked at General Motors Japan for 13 years.

•He was a typical gourmet and loved good food.

In 1907 Mr.Yamashita (aged 18) went to the U.S.A. to follow the American dream.

He started off working as a servant for a rich American family as well as working in a restaurant doing dishes.

His real passion was working on Ford Model-T cars. If he was repairing one, he wouldn’t stop until it was finished – not even for dinner.

Mr.Yamashita finally got his break when he was given a job interview by non other than Mr. Henry Ford himself. Mr. Ford was so impressed he hired him to work for Ford Motor Co. – the first foreigner ever to work there!

He lived in the USA for 18 years in Kansas City, got married and had two sons – the first was named Henry after Mr. Ford.

Training at General Motors - 1935

In 1927 Mr.Yamashita had returned to Japan and was Vice-President of General Motors Japan Co. Ltd.

His grasp of the English language was almost perfect and his long association with Ford Motor Co Ltd meant he was very well acquainted with technical details of the cars.

1940 the closure of General Motors Japan was necessary due to political pressures arising from the war.

Mr. Yamashita established a company ‘YAMASHITA KOGYO co., ltd.” in Osaka. He applied for the Ko-ken brand in Japanese characters as a trademark.

Bomb damage over Osaka

A copy of official bulletin of trademark.

Name card of Mr. Yamashita as the president of YAMASHITA KOGYO co., ltd.

All the employees of Ko-ken 1952

Mr. Yamashita returned to his home town of Daito SHIZUOKA at the end of 1945. The following year he founded Ko-ken Tool Co. Ltd.

Initially the factory was established in a reconditioned warehouse formally used for farming

Installation of 150 ton friction press -1954

In 1954 a 150 ton friction press was installed. The press was to be used for the forging of ratchet bodies.

The industrial level of Japan was still very low and heavy trucks were mostly second hand from the American army.

The boy standing in front of the big trailer truck is Mr. Sho Yamashita (1946 - 2006). He was around 8 years old at the time.

Getting ready for expansion - 1956

To further expand the factory a Shinto- ceremony was held (1956).

The following year, rice fields in front of factory were reclaimed and foundations built ready for the new factory and office.

The three wheel truck is a Mazda and pickup car is a Nissan

Even further expansion

In 1961 Koken took on an extra 6 staff bringing the total to 50. Most stayed with Koken until their retirement.

In the office they had Rockwell and Vickers hardness testers, with torque testing carried out using their own made machinery

In 1962 further expansion plans were put in place.

New factory was completed in 1964

The new factory was finally completed in 1964. It was made from steel frames and slate instead of wood and tiles

Latest view of Ko-ken Tool co., ltd.

Today Ko-ken has more than 30,000m² ground and 13,000m² floor for factory and office use.

Inside the Koken factory most lathes were belt driven from a power shaft located on the upper beam of the factory

The slotter machine (behind Mr. Yamashita) was fully automatic and made ¾” and 1” square drive sockets. This was replaced once a bigger crank press was obtained.

Early machinery

These early machines have been restored and are now displayed in the Koken office.

Early machinery

2 kinds of presses

A 150 ton friction press was installed in 1954. This was the biggest machine in the factory until 1970- when an 800 ton knuckle crank press was installed

In 1961 saw the introduction of a new 150 ton crank press was

The original factory door was too small to get the machine in, so they had to remove part of the wall to do so and repair it later.

This allowed Koken to produce up to 70mm opening sockets by hot forging.

Skilled Workers

New lathes came with built-in motors

The sockets were turned piece by piece and most measurements were made by the skill of the individual turner.

At that time, Koken was very reliant on the worker for producing good quality products.

Skilled Workers

Ko-ken started exporting sockets and accessories in 1957/1958.

Before packing, every individual product was inspected to the very last detail.

Koken was one of the first to adopt such a rigid ‘quality control’ process.

New Zealand was the first export market for Koken and continues to be a strong supporter of the brand

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