expression
yes it is!; it surely is; certainly
Used as a strong affirmative response, often in reply to a preceding まさか…? question expressing disbelief. Conveys 'indeed it is so' or 'you bet it is'.
See also: まさか
「まさか、もう終わったの？」「そのまさかだよ。」
"No way, you already finished?" "Yes, indeed I have."
「まさか彼が優勝するとは思わなかった。」「そのまさかだ。」
"I never thought he would win." "But he did, indeed."