RE: Ideographic Space, word-spacing, and justification

If I could add my own interpretation.

In the latest JIS X 4051 implementation that I followed back then (1995), the ideographic space (called Japanese space character) and the regular space (called Roman inter-word space character) had different behavior classes which affected all sorts of Japanese specific typography aspects, concerning expansion, compression, auto-space, character space control, and such.

Historically the regular space character (0x0020) has had many more tweaking that all other space characters encoded in Unicode/10646 (General category property = Zs). There are 18 spaces, only two (0020 and 3000) have some sorts of special treatment. Others are mostly ignored, which is less than optimal. Although most of them have precise desired width, it is always an open issue to determine whether expansion/compression or any other inter-letter spacing should affect the ideal/desired width of these additional space characters.


Saying that ideographic space is only used after ‘?’ and ‘!’ is nice, but text layout has still accommodate its occurrence anywhere in text run, desired or not.


This still does not change my opinion about the question which is to be in agreement with Steve.




From: [] On Behalf Of KOBAYASHI Tatsuo(FAMILY Given)
Sent: Thursday, October 30, 2008 2:00 PM
To: Steve Deach
Cc: fantasai; WWW International; Paul Nelson; Michel Suignard
Subject: Re: Ideographic Space, word-spacing, and justification



Kobayashi-sensei gave me additional information on U+3000.
Following is a brief summary.

In our Japanese Requirement, IDEOGRAPHIC SPACE is only explicitly used as space after [?] and [!].

IDEOGRAPHIC SPACE does not behave as spaces before and after ideographic punctuation characters.

In justification process with expansion method, when too many Han characters and Kana characters are in a row, i.e. there are seldom place to be expanded, IDEOGRAPHIC SPACE can be expanded, however the priority is lowest.

If you have further questions, do not hesitate to raise.


2008/10/30 KOBAYASHI Tatsuo(FAMILY Given) <>

Hi, Erica,

In Japanese Layout, "spacing issue" is one of the most difficult issues to treat.
We intended to carefully eliminate concrete character name like IDEOGRAPHIC SPACE(U+3000) and SPACE(U+0002) from our requirement. Rather introduced three different types of abstract space concepts as follows:

inter character space: usulal 1/2 em fixed space.
conditional space: 1/2 em fixed space to be inserted or pulled off between characters and punctuation marks.  
adjustable space: variable width space, behaves like usual western variable space.

Note that, usual Japanese punctuation marks have 1/2 em width in our requirement, even if the character name might include "FULLWIDTH ‾‾‾"

Anyway, the disition how to deal with these spaces in CSS recommendation and in actual implementation is up to your side:-)


2008/10/30 Steve Deach <>


	No, in my personal opinion, it should not.
	The 2 differences between normal space/nbsp vs ideographic space are:
	 1.) The normal width is different, and
	 2.) The normal space/nbsp is treated as justifying
	     (adjusted by both wordspacing and letterspacing),
	     whereas the Ideographic space should only be adjusted by
	     letterspacing (only if ideographic letters are also so adjusted).
	However, I will re-confirm this with our CJK experts, before claiming this
	is an Adobe opinion.

	On 2008.10.29 15:13, "fantasai" <> wrote:
	> Hello,
	> The CSSWG would like to know whether the IDEOGRAPHIC SPACE U+3000
	> should be affected by 'word-spacing', and whether it should be
	> treated as a space during spaces-only justification or treated as
	> a typical ideographic punctuation character.
	> ‾fantasai

Scholex Co., Ltd. Yokohama
JUSTSYSTEM Digital Culture Research Center

KOBAYASHI Tatsuo(小林龍生)
Scholex Co., Ltd. Yokohama
JUSTSYSTEM Digital Culture Research Center

Received on Thursday, 30 October 2008 21:43:10 UTC