Inkan Seals as Tools of Labor Selection in Early 20th Century Mining

In this study, I analyze a hiring mechanism prevalent in the coal mining industry in the first decade of the 1900s by investigating ‘job applications’, which are assumed to have functioned as employment contracts. These job applications include the names, ages, addresses, and previous occupations of 775 applicants, as well as the names of respective referrers, all of which have been compiled in a database. It is noteworthy that some of the applicants affixed personal seals to their job applications. At the time, the use of seals—a traditional Japanese practice—was not pervasive throughout the entire citizenry, as it is now. Coal miners of that era tended to be rustic people with little formal education who were accorded a relatively low socio-economic status. In this article, we explore possible motivations underlying their use of seals. Our results indicate a statistically significant tendency toward the use of seals among these relatively low-skilled workers, as well as a tendency for applicants who used seals to be hired directly by the mining company, rather than through referral hiring, even though the latter was widely used at the time. These trends are consistent with the supposition that the company sought disciplined and diligent workers to hire people who owned seals. This is also consistent with the supposition that low-skilled workers employed seals as a signal to project an image of diligence.