In the 1980s, the whole literary works published by Kenyu-sha Company were revaluated, and the study of the souces and ideas for those novels was developed; as the result, a theory became dominant that this novel was based on American novels.
1980年代になって、硯友社文学全体の再評価の中で、典拠や構想についての研究が進み、アメリカの小説にヒントを得て構想されたものであるという説が有力になった。