[7] A team of four engineers in the motorcar group of the Technical Bureau participated in the development of the medium tank, including a young army officer, Major Tomio Hara.

[1] The Army Technical Bureau set out the specifications, including:[8] Like all weapons, the year of introduction is the first criteria.

At the time, there was little heavy industry allocated to the production of motor vehicles in Japan, so there were significant difficulties creating the prototype.

[14] The tank chassis had a complex parallelogram suspension system with two pairs of road bogie wheels per leaf spring arrangement.

[3] Hara later designed a bell crank scissors suspension, which paired the bogie wheels and connected them to a coil spring mounted horizontally outside the hull.

[15] Many IJA generals and staff attended the field trials of the Chi-I at the Fuji Training Grounds.

[17] The Type 89 was subsequently re-classified as a "medium tank" because the weight increased to over 10 tons due to improvements.

As the army's Sagami Arsenal lacked the capacity for mass production, a contract was awarded to Mitsubishi Heavy Industries, which built a new tank factory to specifically produce this model.