As the first Editor-in-Chief of Primate Research (PRES), Yukimaru Sugiyama established a policy placing a premium on the following three categories of articles: review, opinion/information, and research report/material. He wrote a research report entitled “Studies on Primate Research,” in which he assessed the first nine volumes of PRES, and determined that the journal had reached almost satisfactory numbers of the aforementioned categories of articles (Sugiyama, 1994). He was also satisfied with the balance among fields of expertise, in terms of the number of articles. His recent opinion article repeatedly criticized the Editor-in-Chief and Editorial Board for not following the policy in 2006 and 2016, and the Editor-in-Chief and Editorial Board responded. However, the debate was not based on quantitative data. Therefore, following the methods of Sugiyama (1994), this study examined the number and pages of articles in each article category and in each field of expertise across the three terms separated by Sugiyama's two opinion articles, i.e., I: 1985-1993; II: 1994-2006; and III: 2007-2016, in order to evaluate the validity of Sugiyama's criticism. The numbers and page counts of both reviews and opinion/information articles in one regular issue were greater in term III than in term I. The numbers and page counts of research reports in one issue were greatest in term II, when one special issue as well as two regular issues were published in a single volume. Thus, Sugiyama's criticism is proven to be beside the point. On the other hand, the proportion of articles in socioecology increased, and reached more than half of the total content in term III. This issue should be addressed not only by the Editorial Board, but also by the Secretariat of the Primate Society of Japan.