Translation guide
In Japanese, 'this day' is rarely translated literally. The most natural equivalent depends on whether you mean 'today', 'this very day' (emphatic), or 'this day' in a narrative or formal context.
The speaker refers to the current calendar day in a neutral, everyday context.
The standard word for 'today'. Use this in almost all everyday situations.
今日はいい天気ですね。
It's nice weather today, isn't it?
今日の予定は何ですか。
What are your plans for today?
A formal equivalent of 'today', used in business, announcements, and written contexts.
本日はお越しいただきありがとうございます。
Thank you for coming today.
The speaker emphasizes that something happens on this specific day, often with a sense of importance or immediacy.
Literally 'this day', used to emphasize a particular day, often in narratives or when referring to a significant day.
この日をずっと待っていました。
I've been waiting for this day for a long time.
この日がついに来た。
This day has finally come.
Emphasizes 'this very day called today', often used in reflective or poetic contexts.
今日という日を忘れない。
I won't forget this day.
The speaker refers to a specific day in a narrative, often not the present day.
Used in storytelling to refer to a particular day previously mentioned or understood from context.
この日、彼は運命の決断をした。
On this day, he made a fateful decision.
Means 'that day', but can correspond to 'this day' in English when the day has already been introduced in the narrative.
そして、その日がやってきた。
And then, this day arrived.
Directly translating 'this day' as この日 (kono hi) in everyday conversation about today sounds unnatural. Use 今日 (kyō) for 'today' unless you specifically want to emphasize the day in a narrative or emotional way.