N2 · Structured courses

～Koto Da: Should / It's Best To

Learn koto da for advice based on experience — "it's wise to." This lesson combines form, context, examples, common mistakes, and practice so you can use the pattern in real communication.

12 minNihongo Hub Editorial TeamPublished 2026-06-06Updated 2026-06-06

Learning objectives

  • Lesson goals: Learn koto da for advice based on experience — "it's wise to."
  • Form and connection: [Verb辞书形/なi-adjective] ことだ
  • Nuance in real use: ことだ carries the authority of "someone who's been there" — it's not a negotiated suggestion but "trust me on this." In Japanese mentor-mentee relationships, this expression feels natural.

Form and connection

[Verb辞书形/なi-adjective] ことだ

Core Explanation

Learn koto da for advice based on experience — "it's wise to."

Cultural Note

ことだ carries the authority of "someone who's been there" — it's not a negotiated suggestion but "trust me on this." In Japanese mentor-mentee relationships, this expression feels natural.

Practical examples

You should go to bed early.
If you want to succeed, you must not give up.

Common pitfalls

Build the base form before adding the pattern

Complete the required conjugation first. Do not keep polite and plain endings at the same time.

Match politeness to the situation

The examples are reliable starting points; relationships and context can still change the most natural wording.

Practice and answers

1. Write the connection formula for this lesson.
Show answer[Verb辞书形/なi-adjective] ことだ
2. Explain the meaning of the first example.
Show answerYou should go to bed early.
3. Rewrite the final example using this lesson pattern.
Show answer成功せいこうしたければ、諦あきらめないことだ。 ([Verb辞书形/なi-adjective] ことだ)

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