Dear CJK experts,

I am looking to add furigana (readings) above the Kanji (Chinese characters)
in a Japanese text.

In XeTeX I'd be used to something translating to

\usemodule[simplefonts]
\usemodule[ruby]
\starttext
\ruby{今日}{こんにち}は
\stoptext

What would be the correct command for mkiv?

Many thanks.
Severin