The structural characteristics of the Japanese paperback book series Shinsho

Books constitute an important and dominant part of the knowledge infrastructure. It is generally held that the form, structural characteristics, and symbolic characteristics of books influence how they are read and how they are understood. Nevertheless, a systematic study of these characteristics of books has yet to be carried out fully. Focusing on the Japanese paperback book series Shinsho, whose mission is generally defined as making authentic knowledge available to lay readers, we surveyed the structural characteristics of books, i.e. the depth of the segments (chapter, section, subsection, etc.), the density of segments, how segments are numbered and/or titled, and how the structure of books are represented in the table of contents. We describe the overall characteristics, the chronological changes in these characteristics since 1940, and the association between these characteristics and the subject content of the book. It was observed that as time passed, the density of segments increased in general and converged to the current standard, which consists of three levels of segments (chapter, section, and subsection), among which the top two levels are indicated in the table of contents. Books that deal with literature, however, have a significantly lower density of segments. This study has shown that the structure of Shinsho has changed in the past 70 years. This shed light on how our knowledge infrastructure has been arranged and has changed in a relatively short duration within which we tend to overlook changes.