hanyu: - match: (j|q|x)ü
         subst: \1u
wadegiles: - match: pie\Z
             subst: pieh
           - match: (ts|ch)`eh
             subst: \1`e
           - match: ts`ih
             subst: tz`u
           - match: (k|k`|h)e\Z
             subst: \1o
           - match: (k|k`)ui\Z
             subst: \1uei
           - match: (sh|ch)o\Z
             subst: \1e
           - match: (ch|ch`|ts`|t|t`|l|n|j|s)uo
             subst: \1o
           - match: tsih
             subst: tzu
           - match: sih
             subst: ssu
tongyong: - match: feng
            subst: fong