% 1.pdf
\define[2]\MyChapter{%
	#1 #2: \structureuservariable{subtitle} (\structureuservariable{intro})
}

% % 2.pdf
% \define[2]\MyChapter{%
% 	\setupbodyfont[20pt] #1 #2: \structureuservariable{subtitle} (\structureuservariable{intro})
% }

% % 3.pdf
% \define[2]\MyChapter{%
%     #1 #2:\\
%     \structureuservariable{subtitle}\\
%     (\structureuservariable{intro})
% }

% % 4.pdf
% \define[2]\MyChapter{%
%     \startalignment[flushright]
%         #1 #2:\\
%         \structureuservariable{subtitle}\\
%     \stopalignment
%     \structureuservariable{intro}
% }

% % 5.pdf
% \definemakeup[chapter][align=left, top=]
% \define[2]\MyChapter{%
%     \startmakeup[chapter]
%         #1 #2:\\
%         \structureuservariable{subtitle}\\
%     \stopmakeup
%     (\structureuservariable{intro})
% }


% % 6.pdf
% \define[2]\MyChapter{%
%     \framed[frame=off, offset=0pt]{#1\\#2:\\ \structureuservariable{subtitle}\\ (\structureuservariable{intro})}
% }

\setuphead[title, chapter][command=\MyChapter]

\setupbodyfont[11pt]

\starttext
\startchapter[title=foo][subtitle=bar, intro={some explanation}]
some text
\stopchapter
\stoptext