This issue is applicable to Japanese & Chinese in particular.

Issue jlreq/173 looks at basic support for boten (emphasis) marks and their positioning. This gap report describes some additional aspects of boten handling that need further investigation.

Additional requirements arose while the text was being written for CSS. They relate to text that is annotated with ruby at the same time as annotation marks. The conclusions were:

1. Emphasis marks go outside ruby, as shown by the emphasis dot above the ruby annotations in this example:
   
2. If ruby only spans part of the emphasised word, emphasis marks stay as close as possible to the base, as shown in the emphasis dots on either side of the ruby text.
3. Where a ruby annotation is hidden or empty, the emphasis marks should continue at the same height, as in the following example where the ruby element spans the whole word but no annotation is provided for the second character.
   

There are currently no requirements in jlreq for positioning boten marks with ruby.

[For further research]
JLReq also requires that emphasis marks not appear over commas, full stops and brackets.

JLReq calls out the usual practise of using sesame shaped boten for vertical text, and bullets for horizontal. Controls for this exist in CSS, and tests show that it is supported by the browsers that support boten.

The default side for boten is to the right of vertical lines and above horizontal lines, according to JLReq. CSS controls allow this positioning to be set by the author, and in fact it is the default in both browsers that support boten for text where a lang tag identifies it as Japanese.

The Gap:

Gecko moves the boten marks alongside the ruby annotation, keeping the latter closest to the base.
InBlink, andWebkit, the boten marks disappear when they occur over the same base as ruby annotations.

All browser engines keep the boten marks close to the base text where ruby annotations don't appear.

Tests & results:

Interactive test,Emphasis marks go outside ruby

Spec status:

3.4. Emphasis Mark Position: the text-emphasis-position property Indicates that the default expectation is for boten marks to appear outside the ruby, but also mentions how to hide the marks if that is your preference, or hide the ruby.

Action taken:

TBD:Gecko •Blink •Webkit

Outcomes

TBC

Priority:

If the emphasis marks don't spill over to the text alongside the ruby annotations there is no indication that the text is emphasized, which is clearly a problem.