The HTML <rtc> tag
Quick answer
The HTML <rtc> (ruby text container) element groups <rt> annotations to support complex, multi-level ruby — for example providing both a pronunciation and a meaning for the same base text. It is niche and support varies.
Overview
The <rtc> (ruby text container) element groups a set of <rt> annotations within a <ruby>, enabling multi-level ruby — for example one container for pronunciation and another for meaning over the same base text.
It is rarely needed, and browser support is inconsistent, so reserve it for genuinely complex ruby that requires more than one annotation layer. For the common single-annotation case, a plain <rt> is all you need.
Syntax
<ruby>漢<rtc><rt>kan</rt></rtc></ruby>Example
<p><ruby>東京<rtc><rt>Tōkyō</rt></rtc></ruby></p>Best practices
Frequently asked questions
What is the rtc element?
A container that groups <rt> annotations for multi-level ruby, such as separate pronunciation and meaning layers.
When do I need rtc?
Only for complex ruby with more than one annotation layer over the same base text — most ruby does not need it.
Is rtc widely supported?
No. Browser support is inconsistent, so test carefully or avoid relying on it.
What is the difference between rtc and rt?
<rt> is a single annotation;
<rtc> groups several of them into an annotation layer.