開かい口こう一いち番ばん

adverb

at the very beginning of one's speech; immediately upon opening one's mouth; first of all

Used when someone starts speaking and the first thing they say is notable, often surprising or direct. Common in narrative and reported speech.

• 彼かれは開かい口こう一いち番ばん、辞じ職しょくすると言いった。

  He announced his resignation the moment he opened his mouth.

• 開かい口こう一いち番ばん、母ははは私わたしの成せい績せきのことを聞きいてきた。

  The first thing my mother said was to ask about my grades.