Re: [jlreq] 3.2.6 d: Discussions regarding the amount of inter-character spacing between Kanji and alpha numeric characters (#163)

> It looks like Kobayashi-sensei has produced [some detailed advice](https://lists.w3.org/Archives/Public/public-i18n-japanese/2020JanMar/0014.html) about this in email. Is it worth summarising in English here, for those of us who don't speak japanese?

Kobayashi-sensei's email was about the possibility of narrower-than-quarter-em-spacing. Here's a summary:

1. The design and spacing of Japanese characters and Latin characters are different. In the case of solid setting of Japanese text, if there is no inter-character spacing between Latin characters and Japanese characters, the text looks, hmm, too "solid". Therefore, some spacing between Kanji and Latin characters are needed.

2. There are various combinations of Japanese and alphanumeric characters (as follows). The ideal spacing of each case may be different, but it is difficult to determine the ideal spacing for each case, so the same processing has been performed so far. The same should apply in the future.

```
1) European numerals
2) A Latin letter (uppercase or lowercase)
3) Multiple Latin letters (uppercase and/or lowercase)
4) A word in Latin script (uppercase and/or lowercase)
5) Multiple words in Latin script (uppercase and/or lowercase)
6) Others (like "はJ. M. ケインズである")
```

However, in the cases where the text can be processed individually (like heading or book title), especially in book titles, the text was usually finely adjusted according to the arrangement of the characters. However, in the case of processing a large amount of text automatically, uniform processing will suffice.

3. In letterpress printing, the amount of inter-character spacing between Kanji and alphanumeric characters was quarter em spacing. This was because the size of the smaller letterpress printing material for space were mostly quarter em. Depending on the character size, there were other sizes for spacing such as 1/8 em, 1/6 em, 1 point, etc., but these were too thin and cumbersome to handle, and the number of printers providing those were limited.

4. The reason for the quarter em spacing in letterpress printing was European numerals. Traditionally, when handling of Western text in Japanese text in letterpress printing, the width of European numerals were generally half em. In addition, the lowercase Latin letters were also half em, which was reasonable.

If the character width is half em, the number of characters is an odd number, and the spacing is quarter em, the total width will become an integral multiple of the font size, and line adjustment processing is less likely to happen.

5. In recent years, the width of European numerals in Japanese text is often not half em.

6. In desktop publishing, there are cases in which the space between Japanese and Latin text are be specified narrower than a quarter em.

7. Kobayashi-sensei made a type sample set (from 1/8 em to 1/2 em) about the spacing between Japanese and Western texts in computer typesetting, and took a questionnaire to those who had a comparatively good eye for typesetting a long time ago. Although he didn't find the detailed numbers, he remembered that most of the opinions were that 1/6 or 1/5 em spacing were good.

8. When desktop publishing started to be used in Japan, it was possible to specify quarter em spacing in some desktop publishing software as the amount of spacing between Japanese and Western characters. However, this was not 1/4 em of a full-width character, but 1/4 em of a half-width character, that is, 1/8 em of a full-width character.

One won't know this unless they reads the manual carefully. If they intends to specify 1/4 em, the result may be 1/8 em spacing. Even such a thing was used without causing any problems, indicating that the ideal spacing between Japanese and Western text may be narrower than quarter em.

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Received on Wednesday, 6 May 2020 16:18:56 UTC