Translation guide
How to express forgetting to write something in Japanese, covering both forgetting the action and forgetting to include content.
I forgot to write the report.
Don't forget to write the email.
A slightly more formal alternative using こと to nominalize the verb. Interchangeable with 書くのを忘れる in most contexts.
I forgot to write the letter.
A compound verb meaning 'forget to write'. More concise and often used in casual speech.
I forgot to write my homework.
The speaker wrote something but omitted a specific detail or item.
Used when you forget to write a specific thing within a larger piece of writing. The omitted item is marked with を.
I forgot to write my name.
Please don't forget to write your address.
Can also be used for forgetting to include something, but 書き忘れる is more common for this nuance.
書くのを忘れる emphasizes forgetting the action of writing itself. 書き忘れる often implies forgetting to write a specific item within a document. However, they overlap significantly and are often interchangeable.
I forgot to write my diary (the whole action).
I forgot to write today's events in my diary.
The form 書く忘れる (without の or こと) is ungrammatical. Always use 書くのを忘れる, 書くことを忘れる, or the compound verb 書き忘れる.
I forgot to write that point.