\documentclass[]{article}
\usepackage{tikz}
\begin{document}
\newwrite\kanaoutfile
\immediate\openout\kanaoutfile=KanaData.txt%
\def\xHead{A,I,U,E,O}
\def\yHead{xx, K,S,T,N,H,M,Y,R,W}
% Headrow
yy, --A, --I, --U, --E, --O, N
\foreach[count=\row] \y in \yHead{%
\ifnum\row=1 \y, \else \y-- \fi%
\ifnum\row=1 \xHead, N \else
\foreach \x in \xHead{%
\y\x, } nn \fi
\par}
% Headrow
\immediate\write\kanaoutfile{yy, --A, --I, --U, --E, --O, N}
\foreach[count=\row] \y in \yHead{%
\immediate\write\kanaoutfile{\ifnum\row=1 \y, \else \y-- \fi}%