When romanizing a Japanese title, which words should be capitalized?

Question

Specifically, when you are trying to romanize Kanji titles of movies, plays, written works, etc. for formal writing targeting non-Japanese speakers, what are some good guidelines?

As seen in this English stack exchange question, there are some well established style guidelines for the English-speaking world. I realize this is a question of style, which is a matter of taste, but having some solid guidelines would be better than nothing.

A common sense approach of adapting the English guidelines to their Japanese counterparts seemed viable, but my anecdotal research indicates that commercial publishers/studios only do so half the time. Particularly vexing are compound particles and the Japanese copulae, such as da and desu kedo.

Answer 1

In English, people often capitalize every word in a foreign title, and you can apply that rule without talking about Japanese specifically at all. Of course, different people use different styles! Here's what I'd do:

Capitalize everything except function words (particles, conjunctions, etc.). If a function word is the first word, or if it's long (6+ letters-ish), capitalize it anyway.

That's just me, personally.

---

Although there are official guidelines for romanizing Japanese, I couldn't find any official Japanese guidelines that addressed capitalization as well. That doesn't surprise me—when Japanese titles are written in Japanese, it's almost always with kana and kanji. In other words, although Japanese speakers are of course familiar with romanization, the question doesn't really come up that often in the context of the language itself.

However, you might find the ALA-LC romanization interesting, as it addresses capitalization specifically and is an official system used by North American libraries including the Library of Congress, and in fact is used outside North America as well. (Further ALA-LC romanization tables can be found here.) Since it's not copyrighted, I'll reproduce it here:

Capitalization

1. Personal Names:

   (a) Capitalize each word of a personal name, except the particle no.

        Sugawara no Takasue no Musume            菅原孝標女

   (b) Capitalize title and terms of address, except when consisting of a single character or kana for san, sama, chan, kun, etc., that is hyphenated following a personal name. [...]

        Kōbō Daishi                              弘法大師
        Naikaku Sōri Daijin Tanaka Kakuei        内閣総理大臣田中角栄
   but  Okiku-san                                お菊さん
        naikaku sōri daijin (as a generic noun)  内閣総理大臣

2. Place Names: Capitalize each word of a geographic name.

        Yokohama                                 横浜
        Nihon Rettō                              日本列島
        Yūraku-chō                               有楽町
        Taiheiyō                                 太平洋
        Bōsō Hantō                               房総半島
        Tōyō                                     東洋

3. Corporate Names: Capitalize each word of a corporate name, except particles and conjunctions.

        Sensō o Kirokusuru Kai                   戦争を記録する会
        Nihon Rikugun                            日本陸軍
        Chuō Kōron Shinsha                       中央公論新社
   but  Chuō kōron (journal title)               中央公論

4. Documents and Publications:

   (a) Capitalize the first word of the title of a publication (book, periodical, series, etc.)

        Tsurezuregusa                            徒然草
        Chūō kōron                               中央公論

   (b) Capitalize the first word of the name of a document (law, regulation, etc.).

        Rōdō kumiaihō                            労働組合法
        Rōdō iinkai kisoku                       労働委員会規則

5. Historical Events and Periods:

   (a) Capitalize each word of the name of a historical event, except particles and conjunctions.

        Dainiji Sekai Taisen                     第二次世界大戦
        Niniroku Jiken                           二・二六事件
        Meiji Ishin shi                          明治維新史
        Sekigahara no Tatakai                    関ヶ原の戦い

   (b) Capitalize the first word of the name of a historical period.

        Jōmon jidai                              縄文時代
        Rikuchō jidai                            六朝時代
        Heianchō                                 平安朝
        Shōwaki                                  昭和期

6. Peoples, Languages and Areas of Study Derived from Proper Names: Capitalize names of peoples, languages and areas of study derived from proper names.

        Nihonjin                                 日本人
        Amerikajin                               アメリカ人
        Nihongo                                  日本語
        Nihongaku                                日本学
        Eigo                                     英語

7. Religions and Sects: Capitalize names of religions and sects.

        Bukkyō                                   佛教
        Kirisutokyō                              キリスト教
        Shintō                                   神道
        Zenshū                                   禅宗
        Jōdo Shinshū                             浄土真宗

8. Structures, etc.: Capitalize names of structures, etc.

        Takamatsuzuka Kofun                      高松塚古墳
        Narita Kūkō                              成田空港
        Hibiya Kōen                              日比谷公園
        Eigenji Damu                             永源寺ダム

9. Derivatives of Proper Names: Lowercase words derived from names of places or religions, when the derived words are no longer considered to be proper names. When the derivative is formed by the suffix of a single character following a proper name, the proper name is capitalized and the suffix is lowercased and follows a hyphen. [...]

        nihontō                                  日本刀
        nihonshu                                 日本酒
        nihonga                                  日本画
        butsuga                                  佛画
        washitsu                                 和室
        wafuku                                   和服
        yōshu                                    洋酒
        kutaniyaki                               九谷焼
        kokutani                                 古九谷
        kanji                                    漢字
        kanpō                                    漢方
        kan'yaku                                 漢薬
        zendera                                  禅寺
        zensō                                    禅僧
        kirisutosha                              キリスト者
        rōmaji                                   ローマ字
   but  Taiwan-sei                               台湾製

As I said before, I would rather say "function words" than "particle or conjunction", and I do find one of their examples puzzling (I don't think 史 is a particle or conjunction in 明治維新史), but they seem to be otherwise reasonable guidelines.

Of course, style isn't set in stone—do whatever you think seems best!

Answer 2

If it's a title, then presumably you'd capitalize most words. Japanese だ and です roughly equate to English is, be, and these are capitalized in English titles, so it would make sense by analogy to capitalize the romanizations as Da and Desu. Meanwhile, particles seem loosely equivalent in terms of grammatical function to English articles and prepositions, which usually aren't capitalized in titles.

Thrill to the new movie release, Kore wa Pen Desu!!