+%\tracingall
+\def\showdir{\ifcase\ltjgetparameter{direction} %
+?\or D\or ?\or T\or Y\or ?\or ?\or?\or?\or?\or?\or U\fi}
+\showdir
+\hbox{\tate {\dtou 感じ\showdir}\showdir}
+\showdir
+
+
+\vbox{\tate\hsize=100mm
+日本語中に数式を打ってみる%
+$\ltjgetparameter{talbaselineshift}abc\hbox{にほんごABC\hbox{\tate たて\showdir}}\showdir$
+$$
+ \ltjgetparameter{talbaselineshift}abc\hbox{にほんごABC\hbox{\tate たて\showdir}}\showdir
+$$
+あいうえお}
+
+\vsize250mm
+\def\F#1{%
+\medskip
+\setbox0=\hbox{\csname #1\endcsname
+ \hbox{\yoko Y}\hbox{\tate T}\hbox{\dtou D}\hbox{\utod U}}
+{\obeylines\fivett\baselineskip=7pt
+\directlua{luatexja.ext_show_node_list(tex.box[0], 'hbox #1> ', tex.print)}\par}}
+
+\F{yoko}
+\F{tate}
+\F{dtou}
+\F{utod}
+
+\hbox{\inhibitglue\tate}
+\hbox{\ltjsetparameter{kanjiskip=0pt}\tate}
+
+\leavevmode\hbox{A}%
+\setbox0\hbox{}%
+\setbox1=\lastbox\the\wd1
+\end