The ōshū, rendered on the cover as Racvyoxyv, was a 1598 Japanese dictionary of kanji "Chinese characters" and compounds in three parts. The Jesuit Mission Press published it at Nagasaki along with other early Japanese language reference works, such as the 1603 Nippo Jisho Japanese–Portuguese dictionary. The Rakuyōshū, also known as the Rakuyoshu or Rakuyôshû, is notable as the first dictionary to separate kanji readings between Chinese loanword on (音 "pronunciation") and native Japanese kun (訓 "meaning").
In contrast with the numerous Rakuyōshū studies written in Japanese, the primary research in English is by Joseph Koshimi Yamagiwa, Professor of Japanese at the University of Michigan, and Don Clifford Bailey, Professor of Japanese at the University of Arizona.
Title
Although the title Rakuyōshū (落葉集) literally reads as a shū (集 "collection; assembly") of rakuyō (落葉 "fallen leaves", or ochiba 落ち葉 in kun reading), the preface explains it metaphorically means "collection, in iroha order, of fallen (left-over, overlooked) words". To be sure, many Japanese dictionaries have appeared in the world before now. Of these, however, it may be said that they are deficient either in that they provide the koe [Chinese reading] of characters, omitting the yomi [Japanese reading], or that they record the yomi and ignore the koe. Herein we propose to assemble "left-over [rakusaku]" kanji and compounds long in use but hitherto overlooked and to arrange them, after the manner of the Irohashū, in iroha order, their on [Chinese readings] to be on the right and their yomi to be on the left, and thus to produce in one volume a dictionary to be designated the Rakuyōshū. Thereafter we propose to add a section of characters and compounds similarly grouped in iroha order but arranged in terms of their Japanese readings. Rakusaku comes from the Classical Chinese word luosuo (落索 "wither, shrivel; fall low, fall on hard times; lonely, lonesome"). Thus, the title blends raku (落 "fall; drop") meaning words "dropped" (overlooked, missed) by other Japanese dictionaries plus yōshū (葉集, or hashū in on-reading) abbreviating Irohashū (色葉集 "iroha collection") meaning a dictionary collated in iroha order (e.g., the 12th-century Iroha Jiruishō). Despite the compiler's intention of including overlooked words, Bailey discovered that more than half of the Rakuyōshū entries are found in contemporary Japanese dictionaries, primarily 15th-century Setsuyōshū editions, and many others occur in Chinese rime dictionaries.
Contents
The Rakuyōshū text comprises 108 folios (chō 丁 "leaf of paper, folio; block") in three parts, succinctly described by Joseph Koshimi Yamagiwa. (1) A 62-folio section consisting of (a) the Rakuyōshū proper, which is a listing of Chinese-Japanese characters (kanji) and compounds arranged in terms of their on pronunciations, that is, the pronunciations borrowed into Japanese from Chinese, (b) a list of the characters used in writing the numbers, and (c) some errata; (2) a 27-folio section consisting of (a) the Irohajishū 色葉字集, which is a listing of kanji and compounds arranged in terms of their kun pronunciations, that is, the pronunciations of the Japanese words represented by the Chinese characters, (b) some errata, (c) a listing of the names of one hundred Japanese government offices together with their Chinese equivalents, and (d) a listing of the sixty-odd provinces of Japan; and (3) a 19-folio section consisting of (a) the Shōgokuhen 小玉篇, which is a listing of the kanji in terms of 105 'radicals,' and (b) some errata.
Part (I), entitled the Rakuyōshū, gives Chinese on readings of kanji and kanji compounds. It includes nearly 1,700 main character entries (boji 母字 "mother character; head character") with approximately 12,000 run-on entries of multi-character compounds (jukuji 熟字 "compound; idiom; phrase").
Part (2), the Irohajishū ("Iroha-ordered character collection"), gives the equivalent Japanese kun readings of kanji. It is less than half the size of (1) and only gives about one-fourth as many kanji compounds, around 3,000. The Irohajishū frequently lists graphic variants that have homophonous kun readings, for instance, defining hō 芳 "fragrance; aroma", fun 芬 "sweet smell; fragrance; perfume", and kō 香 "scent; aroma; fragrance; incense" as Japanese kōbashii "nice-smelling; savory; aromatic; fragrant; favorable". This part includes two appendices: the Hyakkan narabi ni Tōmyō no taigai (百官並唐名之大概 "Outline of the hundred government offices and their Chinese equivalents") and the Nippon Rokujūyoshū (日本六十餘州 "The 60-odd provinces of Japan") gazetteer.