This paper discusses the pachinko industry's tremendous market expansion and development in the 1980s through an examination of factors related to the transformation of pachinko parlor management during this period.

The first factor in this development is related to increasing stability of the profit structure of parlors that occurred as sales fluctuations became smaller, a trend spurred by the sudden rise in sales brought about by greater enthusiasm for gambling. At the same time, management became increasingly independent as it no longer needed to readjust the individual pins on game boards, a process that required a great deal of technical skill.

The second factor is related to the supply system of the ‘Fever’ machine, which occurred in response to the pachinko boom. Since there is high fluctuation in demand, machinery manufacturers generally do not have sufficient production facilities to fill orders in a short period of time when popular models appear. However, in response to the sudden popularity of the ‘Fever’ machine, other makers, in addition to the original manufacturer, started to produce and supply imitations, making it possible to meet expanded demand throughout Japan.

On the other hand, competition became more fierce as many new parlors entered the market, enticed by the industry's growth potential. Parlor management, which had previously relied on, among other things, technical expertise related to pachinko board pin adjustment, now found itself confronted with limitations. The industry thus sought new management approaches as it attempted to come to terms with the new situation.

The purpose of this paper is to analyze the medium-sized munitions companies which grew rapidly in the interwar period, focusing on Watanabe Tekkojo (Watanabe Engineering Corporation).

In 1886, Watanabe Tekkojo was established as the supporting section of a wholesale merchant of metal products in Fukuoka. It had expanded into munitions in 1902, when Fukuo Watanabe became one of the executives in the company. He had experience of working in the military section of Ishikawajima Shipbuilding & Engineering Co., Ltd. Watanabe Tekkojo made advances to the Imperial Japanese Navy in WW I, and received orders for parts of torpedoes and torpedo tubes from the navy. The orders increased after the Washington Naval Treaty. In the 1930s the navy built up military aircrafts because of the London Naval Treaty, so Watanabe Tekkojo began to manufacture parts of aircrafts.

In the past studies about the Japanese munitions companies, the military sections of the Zaibatsu Konzerns had attracted attention as the center of the private military companies. Accordingly, it has been defined that the military influence in the Japanese economy was reduced in the disarmament period before WW II. However, the Imperial Japanese Navy also made advance to the medium-sized companies. As a result, the range of the munitions industry was expanded in Japan. The Imperial Japanese Navy gave technical guidance to the medium-sized munitions companies, dispatched able engineers to them, helped the procurement of their capital and materials and so on.

The change in the interwar period led the Japanese military production system to the wartime economic controls in WW II. Aircrafts and the others munitions were made by not only arsenals and the Zaibatsu Konzerns but also many medium-sized munitions companies.