By Tony Graham

Designing Japanese documents

In order to provide guidance to those involved in the preparation of documents for the Japanese market, a special Japanese layout taskforce has developed the “Requirements for Japanese Text Layout”. Here is an insight into the content.

A recent publication by the World Wide Web Consortium sheds light on the layout requirements for Japanese documents.

The Working Group Note "Requirements for Japanese Text Layout" was published simultaneously in English and Japanese and is largely based on the Japanese Standard for layout, JIS X 4051. JIS X 4051 is published in Japanese only, so the English-language Note provides a unique guideline of how to layout Japanese text.

The Note was developed by a special Japanese Layout Task Force (JLTF) that included both Japanese experts and members of the CSS, Internationalization Core, SVG, and XSL Working Groups. After a working period of over two years, the JLTF published the Note on June 4, 2009.

It describes considerations of aesthetics and readability and provides comparisons of particular features as well as many more technical details and figures illustrating the finer points. The Note is useful for page designers as well as software developers.

The final document uses English terms where possible, and Japanese romaji (Latin transliteration) where there is no close English term. The publication highlights terminological differences and discrepancies in the initial approach of designing a page.

Pages from the inside out

In the Western tradition, pages are designed from the outside in: the page size is decided first, followed by the size and placement of the main text block. Headers and footers are placed relative to the page edges.

In the Japanese tradition, it is the opposite: the size of the main text block (kihon-hanmen) is determined first, headers and footers are located relative to the kihon-hanmen, and the size of the page (trim size) is determined based on the proportions of the kihon-hanmen. The kihon-hanmen size is determined by typeface, character size, characters per line, number of columns (and the gap between columns), lines per page, and the gap between lines (see graphic 1).

Japanese characters – whether ideographic (kanji), hiragana, or katakana – are designed to fit into a square box (the character frame, see graphics 2 and 3). Japanese text can be set either vertically or horizontally, and, with few exceptions, characters have the same appearance in both writing modes. About the same number of books are set with vertical text as with horizontal; however, horizontal writing is recommended for documentations and most educational material. Character size is typically 9 point, with a minimum of 8 point, except for dictionaries and other specialized publications.

Japanese text is most readable when there is no space between the characters. The line length, therefore, is specified as the number of characters per line. Recommended maximum line lengths are 52 characters for vertical text, and 40 characters for horizontal text. If the trim size is much larger than this, consider using multiple columns.

The line gap is measured between the bottom (or left) of the character frames of one line and the top (or right) of the character frames of the next line. The line gap is typically between half the character size and the full character size. This is proportionately larger than is common for Western text, but there is a lot more that fits into the line gap, including ruby (indicating pronunciation or meaning), emphasis dots, subscripts, superscripts, and warichu (inline cutting notes). The line gap does not vary between lines in the main text, so it needs to be designed to accommodate all the embellishments that may be used while being small enough to achieve good readability (see graphic 4).

The headers and footers are typically positioned relative to the kihon-hanmen by a multiple of the main text character size (see graphic 5).

The trim size should have similar proportions to the kihon-hanmen. The kihon-hanmen is most often positioned centrally in the trim size, or can be positioned by specifying the offsets from the kihon-hanmen to the gutter and/or the page foot (see graphic 6).

Having got the page right, you can think about the text on the lines of the page.

A different kind of grid

Many of us look at the kihon-hanmen as a grid. Actually, the kihon-hanmen is more a set of line-length slots than it is a grid. Japanese characters are square, but there are many other aspects – such as proportional Latin text and half-width punctuation characters – that interrupt the progression of regularly-sized characters. The typesetter, or these days the layout software, makes sure that each line starts and ends at the edges of the kihon-hanmen. Within each line we can add or remove a small space between characters. The last line in a paragraph is usually not adjusted unless the adjustment would prevent a following line or even a page with only one character (see graphic 6).

There are multiple ways to represent Latin characters: as full-width characters in the same size as the ideographs; as fixed, half-width characters; or as characters with proportional width. In vertical text, the Latin characters may be set in normal orientation (common for full-width), rotated 90 degrees clockwise; or alternatively in tate-chu-yoko (horizontal in vertical setting), where 2-3 proportional or half-width characters are set horizontally side-by-side. Space is typically added between Japanese and Latin text to improve readability (see graphic 7).

Punctuation characters are normally half-width, with extra space normally added before and/or after to fill the character frame. The extra space may be omitted or reduced in sequences of punctuation characters or at the start or end of a line. It may also be reduced or expanded when fitting the line to the kihon-hanmen (see graphic 8).

Some characters may not start a line, and others may not end a line, and some sequences may not break over a line. Full stops and commas may not start a line, but they alone may "hang" outside the kihon-hanmen at the end of the line. The Note advises us to avoid hanging punctuation when mixing Japanese and Latin text on the basis that it is not common in Western typesetting (see graphic 9).

Mathematical or chemical formulae, when set inline with text, are set solid (without space between characters) but with space between non-Japanese characters and Japanese text. In contrast, formulae set as lines on their own are set with additional space around math operators, and the Note shows two alternative styles for adding the spaces (see graphics 10 and 11).

Where to go from here

This has necessarily been only a small portion of the material in the "Requirements for Japanese Text Layout". If you are involved in preparing documentation for the Japanese market, we recommend the download of the Note to improve the appearance of your own documentation.

Before you get started you should ask yourself whether you can produce a Japanese-specific design. If you are following a corporate style or if you are restricted regarding design for some other reason, make sure that you have enough wiggle room allowing you to, for example, change the character size, the line length or line gap.

You can find the full Note here:

www.w3.org/TR/jlreq