\documentclass{ltjarticle}
\makeatletter
+\def\mdseries@mc{el}
+\def\bfseries@mc{sb}
+\def\mdseries@gt{l}
+\def\bfseries@gt{k}
+\DeclareFontShape{JY3}{gt}{k}{n}{<-> KozGoPr6N-Heavy.otf:jfm=ujis}{}
+\DeclareFontShape{JT3}{gt}{k}{n}{<-> KozGoPr6N-Heavy.otf:jfm=ujisv}{}
+\DeclareFontShape{JY3}{gt}{l}{n}{<-> KozGoPr6N-ExtraLight.otf:jfm=ujis}{}
+\DeclareFontShape{JT3}{gt}{l}{n}{<-> KozGoPr6N-ExtraLight.otf:jfm=ujisv}{}
+\DeclareFontShape{JY3}{mc}{el}{n}{<-> KozMinPr6N-ExtraLight.otf:jfm=ujis}{}
+\DeclareFontShape{JT3}{mc}{el}{n}{<-> KozMinPr6N-ExtraLight.otf:jfm=ujisv}{}
+\DeclareFontShape{JY3}{mc}{sb}{n}{<-> KozMinPr6N-Bold.otf:jfm=ujis}{}
+\DeclareFontShape{JT3}{mc}{sb}{n}{<-> KozMinPr6N-Bold.otf:jfm=ujisv}{}
\def\TEST{%
\par
A: \f@encoding/\f@family/\f@series/\f@shape.
あいうABC
}
\begin{document}
+\TEST NORMAL
+\emph{\TEST} EMPH
+\textsf{\TEST} SF
+\textbf{\TEST} BF
+\textgt{\TEST} GT
+\textbf{\textgt{\TEST}} BF+GT
+\textbf{\textgt{\textmd{\TEST}}} BF+GT+MD
+
+\textsc{\textit{\TEST}} SC+IT
+
+{\fontseries{b}\selectfont \TEST} B
+{\fontseries{bx}\selectfont \TEST} BX
-\bfdefault
-\TEST
-\emph{\TEST}
-\textsf{\TEST}
-\textbf{\TEST}
-{\fontseries{b}\selectfont \TEST}
-{\fontseries{bx}\selectfont \TEST}
-\textsc{\textit{\TEST}}
\end{document}
\ No newline at end of file