 The full etymology is unknown . The oldest known usage of the word is in the 794 text Shin 'yaku Kegonkyō Ongi Shiki . Other old sources include Nihon Ryōiki ( 810 – 824 ) and Wamyō Ruijushō ( c . 934 ) . These oldest sources are written in Man 'yōgana which clearly identifies the historical spelling as ki1tune . Following several diachronic phonological changes , this becomes kitsune . 
 The full etymology <a href='drop_aux' title='1'><mark>is</mark></a>unknown . The oldest known usage of the word is in the 794 text Shin <a href='null_genetive' title='2'><mark>'</mark></a>aku Kegonkyō Ongi Shiki . Other old sources include Nihon Ryōiki ( 810 – 824 ) and Wamyō Ruijushō ( c . 934 ) . These oldest sources are written in Man 'yōgana which clearly <a href='uninflect' title='3'><mark>identifies</mark></a> the historical spelling as ki1tune . Following several diachronic phonological changes , this <a href='uninflect' title='4'><mark>becomes</mark></a> kitsune . 
Da full etymology unknown . The oldest known usage of the word is in the 794 txt Shin  aku Kegonkyō Ongi Shiki . Other old sources include Nihon Ryōiki ( 810 – 824 ) and Wamyō Ruijushō ( c . 934 ) . These oldest sources r written in Man 'yōgana which clearly identify the historical spelling as ki1tune . Following several diachronic phonological changes , dis become kitsune .