千ち代よに八や千ち代よに

adverb

for millennia and millennia; forever and ever

Archaic adverbial phrase expressing an extremely long time, often used in classical poetry and blessings. The phrase is fixed and not productive in modern Japanese.

• 「千ち代よに八や千ち代よに」は、君きみが代よの歌か詞しにも見みられる古ふるい表ひょう現げんだ。

  "Chiyo ni yachiyo ni" is an old expression also found in the lyrics of Kimigayo.