Hatchback Kei-car that flap its wings in 1970s


Takio Nakagawa

―― 1st gen Minica light van based passenger car

The history of Mitsubishi’s Kei-car began with the Mitsubishi 360, a light van launched in March 1961. As a derivative of the Mitsubishi 360, a 3-box style passenger car with a different rear design was launched in 1962. This was the birth of the Minica, Mitsubishi’s first passenger Kei-car, and its name was short for “minimal car”. Throughout the eight years of sales of this 1st gen. model, with minor changes, its performance contributed greatly to the foundation of the Shin Mitsubishi Heavy Industries Automotive Division. However, user demands became more sophisticated with each passing year, and the demand for passenger car-like ride comfort and sensation, as well as engine output, fuel economy, and smoke emissions, all called for further improvements. The development of the 2nd gen. Minica began in 1966.

Mitsubishi 360(left)1st gen. Minica(right)

―― Differences in basic structure of Minica ’70 from 1st gen Minica

The body was made monocoque to reduce weight, and the suspension was changed from a leaf spring type to a strut type in the front and a 5-link/coil type in the rear to improve ride comfort. The drive system remains the same, with the rear-wheel drive.

―― Full-model changed full-scale Kei-car

The challenge was to create a design that would allow adults to relax comfortably within the legal dimensions of Kei-car, with a beautiful style. At the time, Mizushima Works’ design team consisted of 12 members in the Design Subsection of the Planning and Engineering Section. The company was in its infancy, and the design and development system was being put in place one by one. There was never enough time to acquire basic knowledge in areas ranging from design and model-making to ergonomics, aerodynamics, and production technology. It was a race against time to build a system while putting it into practice.

―― New idea for Kei-car

In those days, the mainstream passenger car was a notch-back style with a trunk lid. However, we introduced a fastback style with a large rear interior space and a wide-opening rear gate for easy loading and unloading. This was the very first attempt for Kei-car, and It was difficult to design a car that would make the most of the difference from the image of a commercial vehicle (van).

Drawing work at studio (left) Full-size rendering(right)

―― Limited dimension interior space

We struggled to set up a spacious interior with openness. Back then, there were no 3D measuring instruments, 3D mannequins, measurement data systems, etc., and ergonomic verification was by 2D. Therefore, a seating buck was made to verify the interior space. The Minica’s package required millimeter-by-millimeter refinement, particularly with regard to head clearance in the rear seats, which required concrete actual measurements by human beings. Therefore, when the seating buck was made, a tall person with an ergonomic 90th percentile was used as a model for verification. The model was Hiroshi Matsuoka (186 cm tall), a future Yakult Swallows ace pitcher, who was working in the labor section at the time, and we were able to verify that sufficient rear seat space was provided.

Seating buck in early stage

―― In the meantime, 3D measuring machine in new employee’s paper

A short time later, Nobutaka Imada, an apprentice, presented a plan for an interior 3D measuring machine in his paper for promotion to a position that should solve the problem of interior measuring. It was a well-designed idea. This led to him being put in charge of interior design.

―― Interior design

The dashboard was designed by Shinichi Kobayashi, and was a unified design by large-scale injection molding, resulting in a simple, ID-like design. Imada designed the seats. He visited the seat manufacturer with his design and worked enthusiastically on everything from the urethane shape to the sewing process, resulting in a good design.

Dashboard model

―― Aerodynamics is future

The first model was completed. Then the prototype was built by inviting sheet metal workers from Carrozzeria Coggiola of Italy to the Mizushima Works to study prototype making. The prototype car was well made, but the design was flat and boxy, so Managing Director Tomio Kubo instructed us, “From now on, we must consider aerodynamics, and you should visit Mr. Kiro Honj (renowned aircraft designer), our adviser, to learn aerodynamics.”

We immediately went to the head office to learn the theory. Returning to Mizushima, we made a 1/5 model based on the theory. The model reflected Honjo’s theory: small frontal projected area, rounded corners, smooth surfaces, posture with an angle of attack, and the rear should fit smoothly like a drop of water, but if this was not possible, the rear end should be cut off. When we painted this model in red, Kubo said, “This is a Dharma!” I was shocked by his severe comment! This was the first aerodynamic model I experienced, an immature and unpolished aerodynamic model. Although I learned a lot from the materials that filled my notebook, it was impossible for a Kei-car with such strict dimensions.

―― Back to square one

Back then, Italian carrozzerias were flourishing, and most Japanese companies were making use of them. Managing Director Kubo decided to appoint an Italian car designer, so he went to Italy and asked Giorgetto Giugiaro, an up-and-coming car designer who was 29 years old, to design the successor of the Colt 800. Furthermore, it was decided that a prototype car would be built in Turin, where sheet metal technology, including large press dies, was advanced. However, when the first prototype was completed, the project was canceled for marketing reasons. Masaru Okano, a senior member of the design group, went to Italy to check the design and reported the results. The executives told us that the prototype design was well done and directed us to use the best parts as a reference for the design of the Minica ’70.

Early design proposal

―― It affects Minica ’70

This lit a fire of youthful enthusiasm. This kind of order is the most annoying. It’s like mixing hot coffee with iced coffee; you lose the best of both worlds. We designers were repulsed by this because our work was going so well. But then it inspired us to further improve our design.

―― Conflicts generate power

Overtime work followed, and there were even some all-nighters. We also worked for the first time on a see-through model, in which a once-completed clay model is torn down, replaced with a wooden cabin, and windows are applied. This process was time-consuming. When we presented the model to the executives, they considered it a very skillful application of the good points of the Colt 800 successor design, and said it was very well done.

See-trough clay model near final design

model front Model refined with reference to Colt 800 successor design by Giugiaro.
  model rear


―― Prototype by Italian battilastra

The design was completed, and the rest of the process moved smoothly from the body line drawing and the prototype to the testing. Of special note in this process was the prototype car. With the aforementioned Italian winds blowing, it was decided to commission the prototype to carrozzeria, this time to Fisore, to master the sheet metal forming technique.

Originally, carrozzeria itself was cultivated through the cooperation between designers and sheet metal workers (battilastra), to meet the orders of aristocrats and wealthy people, and their workmanship was regarded as a work of art. With this background, battilastra’s creed is to faithfully reproduce the designer’s intentions, and although they never create something new, they have the skill to realize it. Any method of communication is acceptable. They take pride in their ability to create whatever the designer intended and expressed, and their skill was superb. This professional spirit was a lesson not only for those involved in prototype production but also for our modelers.

―― Controversial rear gate

The Minica’70 was the first Kei-passenger car to adopt a rear gate along with a fastback. At the presentation to the salespeople, some criticized it, saying, “Isn’t this a van…?” There was a lot of controversy about it until just before its launch. In the end, the issue was settled by explaining that this would be the mainstream design trend in the future.


―― High-performance GSS (GRAND SUPER SPORTS)  added to lineup

The front grille features a four-light design incorporating fog lamps, and the wheels are of a sporty exclusive design. The image of a sporty car was created. Kobayashi designed the front grille, characterized by the red line, and Imada designed the wheels.  High-performance car boom among Kei-car companies had come.

Minica’70 GSS

―― Closing

The development of the car took many twists and turns, but the enthusiasm of all at Mizushima Works led to its completion, and the car was launched in July 1969 under the name “Minica ’70,” with a wish that the car would spread its wings into the 1970s. Sales were brisk, reaching 150,000 units in the fiscal year 1970, firmly establishing a corner of the Kei-car market and establishing the foundation of Mitsubishi’s Kei-car business. Despite the controversial rear gate, the hatchback style, which is the norm for two-box cars today, became popular in Japan with the success of the Minica´70, and this is probably its greatest achievement.

minica'70Minica'70 interior

August 2021