This is the 3367th most frequent Japanese word.
本番
"本番" means "the actual performance" or "the real thing."
Here, '本番' is used to indicate the actual or main event (the real test).
明日の試験は本番なので準備が必要です。
Tomorrow's test is the real thing, so preparation is necessary.
In this sentence, '本番' refers to the main performance or actual event following preparation.
練習の後、いよいよ本番が始まります。
After practice, the actual event finally begins.
Here, '本番' denotes the critical or real-time situation where the event takes place.