Saikaku Ihara (c.1642～93) was a haikai poet and fiction writer of the Genroku period (1688～1704) in Japan. After publishing the maiden works of Koushoku ichidai otoko (Life of a Sensuous Man;1682), he became the leading author of Ukiyozoushi. In the late eighteenth century, there was a Saikaku revival, inspiring many modern Japanese writers. Saikaku’s works are known for their significance in developing Japanese novels today (Emoto and Taniwaki, 1996).
In this paper, we focus on Kousyoku gonin onna (Five Sensuous Women;1686). This work is well known from Saikaku’s work. According to Teruoka (1949), Kousyoku gonin onna did not have a preface, signature and epilogue but it must be Saikaku’s work. Tsutsumi (1957) mentioned that Kousyoku gonin onna did not have a signature but it was evident it was Saikaku’s work. Emoto (1984) also has argued that Kousyoku gonin onna did not have a preface, signature and epilogue but it is recognized as Saikaku’s work, and I agree with the opinion. These researchers stated Kousyoku gonin onna was written by Saikaku but there is no evidence to support it is Saikaku’s work. The first edition of the work did not have a preface, epilogue, handwritten signature and signature seal, namely it is not described that Kousyoku gonin onna was written by Saikaku. Moreover, Kigoshi (1996) stated that particular information should be stated about the uncertainty of author because material did not exist that described Kousyoku gonin onna was Saikaku’s work before Meiji period (1868～1912).
The aim of this paper is to evaluate the writing style of Kousyoku gonin onna using quantitative analysis. In this paper, we investigate Saikaku’s twenty-four novels. A comparison was needed in order to more accurately characterize the Saikaku’s writing style. In this research we also used Saikaku’s student Dansui Houjyou (1663～1711) ’s three novels.
Saikaku’s database was developed with his researchers, who are editors of Shinpen Saikaku Zenshu (Shinpen Saikaku Zenshu Henshu Inkai, 2000). Since Japanese sentences are not separated by spaces, we added spaces between the words in all of the sentences. In addition, information was added for the analysis. We also used Dansui’s database for comparison, which is developed by Professor Hidekazu Banno and Professor Takayuki Mizutani. TABLE 1 shows a list of works in our database and the number of words in each work. According to our database, there are 572,231 words contained in twenty-four of Saikaku’s works and 53,172 words contained in three of Dansui’s works.
We examined the appearance rate of the particles and auxiliary verbs. These variables have a high appearance frequency and do not relate to the contents of a work.
FIGURE 1 shows the results of the analysis on the appearance rate of the particles using the Principal Component Analysis (PCA). PCA reduces the dimensionality of a data set consisting of a large number of interrelated variables, while retaining as much of the variation present in the data set as possible (Jolliffe, 2002). When applied to the frequencies of high-frequency items in texts, PCA often successfully reveals the authorial structure in a data set (Kestemont et al., 2013). The proportion of variance of the first principal component is 0.22838, it is 0.19375 for the second, while it is 0.15655 for the third; the cumulative proportion up to the third principal component is 0.57868. In this figure, Kousyoku gonin onna is in close proximity to the other Saikaku’s works. This result revealed that Saikaku and Dansui’s works differed in the appearance rate of the particles. Kousyoku gonin onna was far from Dansui’s works. Furthermore, we obtained similar result of the auxiliary verbs.
We conducted the quantitative analysis among Saikaku twenty-four works and Dansui three works. This result revealed that Kousyoku gonin onna possessed the same characteristics as Saikaku's works. From that viewpoint, Kousyoku gonin onna's author is Saikaku. In this study, we used Saikaku’s works and Dansui’s works as datasets and particles and auxiliary verbs as variables. Thus, we need to analyze and compare this issue to the other author's works and variables.
We would like to thank Professor Masakatsu Murakami, Professor Hidekazu Banno and Professor Takayuki Mizutani for their help on our research.
 Emoto, Y. and Taniwaki, M. (1996). Saikaku Jiten. Ouhu.
 Teruoka, Y. (1949). Teihon Saikaku Zenshu Vol.2. Explanation Kousyoku gonin onna. Chuo Koron Shuppan.
 Tsutsumi, S. (1957). Nihon Koten Bungaku Taikei Saikaku Jyo. Explanation Kousyoku gonin onna. Iwanami Shoten.
 Emoto, H. (1984). Explanation Kousyoku gonin onna. Koudansha Gakujutsu Bunko.
 Kigoshi, O. (1996). The Uncertainty of the Authorship: Who Should Decide Koshoku-gonin-onna Belong to Saikaku?. Nihon Bungaku Vol. 45 No.10. pp.59～69.
 Shinpen Saikaku Zenshu Henshu Inkai. (2000). Shinpen Saikaku Zenshu. Bensei shuppan.
 Jolliffe, I.T. (2002). Principal Component Analysis. New York: Springer.
 Kestemont, M., Moens, S., and Deploige, J. (2013). Collaborative authorship in the twelfth century: A stylometric study of Hildegard of Bingen and Guibert of Gembloux. Literary and Linguistic Computing. pp.1～26.