• 一部いちぶ — one part / a portion
• 一致いっち — agreement / match
• 一回いっかい — one time
• 一行いちぎょう — one line

When talking about “一日” as a duration — like spending one full day somewhere — the reading is いちにち.

But when referring to the first day of the month, the special reading ついたち is used. This unique reading comes from old Japanese and is still common in everyday speech and calendars.

一人ひとりで行いきます。
I’ll go alone.

一回いっかいだけ見みました。
I saw it only once.

This kanji means “one” and is read いち in most cases. But the sound often changes in compound words — like いっぽん (one long object) or いっしゅうかん (one week). These small changes help the words flow naturally in Japanese.