Kanji-kana ratio for stylometry?

I ended my blogpost on hiragana frequency as a stylometric indicator with the remark that, rather than the frequency distribution of different hiragana in the text, the ratio of kana to kanji is used as one of several key characteristics in actual stylometric analysis of Japanese texts. I was curious to find out if this number alone could tell us something about the 4 manga text samples in question (2 randomly selected scenes from Katsuhiro Ōtomo’s Akira and 2 series from Morning magazine, Miko Yasu’s Hakozume and Rito Asami’s Ichikei no karasu – in the following text referred to as A1, A2, M1 and M2, respectively). My intuition was that the results wouldn’t be meaningful because the samples were too small, but let’s see:

This time I chose a sample size of 200 characters (hiragana, katakana, and kanji) per text.

Among the first 200 characters in A1 (i.e. Akira vol. 5, p. 16), there are 113 hiragana, 42 katakana and 45 kanji. This results in a kanji-kana ratio of 45 : (113 + 42) = 0.29.

In A2 (Akira vol. 3, pp. 125 ff.), the first 200 characters comprise of 126 hiragana, 34 katakana, and 40 kanji, i.e. the kanji-kana ratio is 0.25.

In M1, there are 122 hiragana, 9 katakana, and 69 kanji, resulting in a kanji-kana ratio of 0.52.

In M2, there are 117 hiragana, 0 katakana, and 83 kanji, resulting in a kanji-kana ratio of 0.71!

6 hiragana, 2 katakana, 3 kanji in A2 (Akira vol. 3, p. 125).

Thus this time the authorship attribution seems to have worked: the two Ōtomo samples have an almost identical score, whereas those of the two Morning samples are completely different. Interestingly, this result contradicts the interpretation from the earlier blogpost in which I had suggested that the scientists in Akira and the lawyers in Karasu have similar ways of talking. The difference in the kanji-kana ratio between Akira and the two Morning manga, though, is explained not only through the more frequent use of kanji in the latter, but also through the vast differences in katakana usage (note that only characters in proper word balloons, i.e. dialogue, are counted, not sound effects).

Ōtomo uses katakana for two different purposes: in A1 mainly to reproduce the names of the foreign researchers, and in A2 to stretch syllables otherwise written in hiragana at the end of words, e.g. なにィ nanii (“whaaat?”) or 何だァ nandaa (“what is iiit?”). Therefore the similarity of the character use in the two Akira samples is superficial only and the pure numbers somewhat misleading. On the other hand, it makes sense that an action-packed scene such as A2 contains less than half as many kanji as the courtroom dialogue in M2; in A2 there are more simple, colloquial words for which the hiragana spelling is more common, e.g. くそう kusou (“shit!”) or うるせェ urusee (“quiet!”), whereas technical terms such as 被告人 hikokunin (“defendant”) in M2 are more clearly and commonly expressed in kanji.

In the end, the old rule applies: only with a large number of sample texts, with a large size of each sample, and through a combination of several different metrics can such stylometric approaches possibly succeed.


Artifacts from Japan, part 5: Morning #43, 2018

Two years ago I already introduced another original Japanese manga magazine here, Weekly Young Jump, but I don’t want to give the impression that all manga magazines in Japan are like that. So here’s a look at a magazine that is also filed under seinen (i.e. targeted towards young adult men), but much more mature.

Language: Japanese
Authors: various
Publisher: Kōdansha
Pages: 400
Price: ¥370 ($3.30 / €2.85)
Website: http://morning.moae.jp/ (Japanese)

Morning (or “Weekly Morning” according to Wikipedia, but the word “Morning” is not on the cover as far as I have seen) is not quite as widely read as Young Jump, but its circulation (well over 100,000 copies per issue) is still huge compared to Western comic magazines. In the past, Morning has run famous manga series such as Gon, Planetes, Space Brothers, and Vagabond.

The copy of the issue at hand (dated October 11, but actually published two weeks earlier) has the same dimensions as Young Jump and the same printing quality (or lack thereof), but already on the outside, the content is quite different: instead of an erotic photograph, there’s a cover image that actually refers to one of the manga inside – グラゼニ / Gurazeni by Yūji Moritaka and Keiji Adachi, a baseball series that seems to be relatively popular in Japan. Inside there is very little editorial content apart from a 4-page interview with Moritaka and film director Hitoshi Ōne.

Which brings us to the manga in this issue. There are roughly 20 chapters of 18 pages on average, and these are the more noteworthy ones apart from Gurazeni:

A particularly striking page from Toshiya Higashimoto's <em>Theseus no fune</em>.

A particularly striking page from Toshiya Higashimoto’s Theseus no fune.

As you can perhaps see from these short descriptions, most of the manga in Morning are set in the real world rather than some fantasy or science fiction setting. Considering Morning and Young Jump alone, the vast variety of manga within the seinen demographic becomes palpable – a variety hardly represented by the few of these titles that have been published in the West.