Japan has old alphabets,
いろはにほへと ちりぬるを
わかよたれそ つねならむ
うゐのおくやま けふこえて
あさきゆめみし ゑひもせすん
and, musical scale ( do, re, mi, fa, so, la, si) is also written with C,D,E,F,G,A,B in europe,
and Japan assigned the begining of japanese alphabets
'イロハニホヘト(いろはにほへと)' to 'ABCDEFG',
so,
C=ハ, D=ニ, E=ホ, F=ヘ, G=ト, A=イ, B=ロ.
Addition:
いろはにほへと~ make sentences and meanings like bellow.
色は匂へど 散りぬるを
我が世誰そ 常ならむ
有為の奥山 今日越えて
浅き夢見じ 酔ひもせず