at the very beginning; first and foremost
A formal, literary expression used to emphasize the very start of something. Often found in written or rhetorical contexts rather than casual speech.
First and foremost, I want to emphasize the importance of this issue.
最初 is the common, everyday word for 'first' or 'beginning'. 劈頭第一 is a much more formal and emphatic literary alternative.
真っ先 means 'the very first' in a more casual, action-oriented sense. 劈頭第一 is formal and often used in speeches or writing.
A yojijukugo (four-character idiom) combining 劈頭 (opening, beginning) and 第一 (first, number one). The exact origin is uncertain, but it follows a common pattern of intensifying a concept by doubling similar-meaning elements.