This paper aims to examine the brand marks of the soy sauce shipped to Edo city by the Takanashi family (now known as Kikkoman Corporation) in Noda town, and clarify aspects of the Takanashi family's soy sauce brands.

The Yamasa Corporation had basically two brand marks during the Edo, Meiji, and Taisho eras. It seems other soy sauce breweries also had few brand marks. Therefore, there has been no study that focuses on brand marks. Meanwhile, the investigation into the Takanashi family clarified they shipped more than ten brand marks for a year during the late Edo era, and shipped 66 brand marks for a year during the Tenpou era. Few soy sauce breweries had as many brand marks as the Takanashi and Mogi families (the Mogi family is related to the Takanashi family). It seems the large number of brand marks is one of their characteristics. Therefore, we identify the differences in their brand marks and explain the reasons for the many brand marks.

The prices of the Takanashi family's brands were classified into between three and five categories; the differences in price denoted the quality of raw materials, mixture proportion and quality of unrefined soy sauce. Particularly, they blended unrefined soy sauces that had different ripeness characteristics. This led to the Takanashi family having many brands. Moreover, there were brand marks called tezirushi (hand marks). Tezirushi were sold individually to wholesalers; they were wholesalers' possessive marks. Tezirushi were made by request for wholesalers, and there were instances where different tezirushi contained the same contents. The reason the wholesalers requested tezirushi was that they wanted to differentiate their sauce from other wholesalers. In conclusion, the many brands of the Takanashi family were an expression of their business policy they tried to meet customer needs, which was one of the factors they had maintained, and increase sales in Edo city market.

This study aims to investigate Nakajima Aircraft Company's airframe business and its production efficiency during WW II in comparison with Mitsubishi Heavy Industries.

During the Pacific War, Japanese aircraft production was essentially based on job shop system for parts fabrication and sub-assembly. Nakajima Aircraft Company the largest aircraft manufacturer of war-time Japan and Mitsubishi Heavy Industries the second largest utilized both job shop and production line systems for their airframe final assembly lines depending on each plant situations. The United States Strategic Bombing Survey reports evaluated that Nakajima's airframe production system was more developed than that of Mitsubishi, which adhered to original, old-fashioned job shop system. This was substantiated from the fact that Nakajima expanded its production by 1944 to more than eight times of its 1941 production, and Mitsubishi produced only three times for the same period.

However, in production efficiency measured by airframe weight produced per month per employee, Mitsubishi was predominant until August to October 1944. A positive correlation was observed between production efficiency and monthly number of airframe production. Mitsubishi's improvement degree of production efficiency agreed well with the estimation by learning curve theory, but Nakajima's improvement of production efficiency far exceeded the estimation. This is considered to be the effect that Nakajima's labor utilization rate, which was approximately half of that of Mitsubishi in September 1943, might have increased rapidly as the monthly airframe production increased. The difference of the final assembly line did not have decisive influence on the production efficiency, but the increase in the number of monthly airframe production was influential.

The production efficiency continuously increased as the monthly airframe production increased, and then dropped sharply from the end of 1944 and after due to the rapid decline of monthly production, which was caused by shortages of essential materials and engines, US air raids from November 1944 and after, factory evacuation, and labor shortage.