(short form) + ka / (short form) + ka dou ka: Beginner’s Guide to “whether/if …” in Japanese

Introduction

Want to say “I don’t know if it will rain,” or “Do you remember when we went”? Japanese uses the embedded-question patterns (short form) + か and (short form) + かどうか to express whether/if and other unknowns.

You’ll use them with verbs like わかる / しる / きく / おぼえている / きめる / しらべる.

1. Core Meanings

The Japanese grammar pattern (short) + か/かどうか is used to express uncertainty or to ask whether something is true or not.

This pattern can be used to form indirect questions, express doubt, or ask for confirmation.

• (short) + か = an embedded question (open or yes/no). Example: いつ雨あめが降ふるか、知しっていますか。= Do you know when it will rain?
• (short) + かどうか = “whether or not …” (yes/no type only). Example: 雨あめが降ふるかどうか、知しっていますか。= Do you know whether or not it will rain?

2. Form (short form before か)

To use the (short) + か/かどうか pattern, you need to place か or かどうか after a short (plain) form verb, adjective, or noun.

Verb

u-verb

ru-verb

irregular verb

Adjective

い-adjective

な-adjective

Noun

Tip: Why does da disappear with Nouns and Na-adjectives?

You learned that the plain (short) form of a noun or na-adjective is Noun/Na-adj + だ (da). However, when you attach か or かどうか to it, the だ is always dropped.

• 彼かれは学生がくせいだ (He is a student.) → 彼は学生かどうかわからない。 (I don’t know if he is a student.)
• この部屋へやは静しずかだ (This room is quiet.) → この部屋は静かか教おしえてください。 (Please tell me if this room is quiet.)

This is a firm grammatical rule to remember.

3. か vs かどうか — Which one?

When the issue can be answered with Yes/No (= “whether or not” sentence), you can use both か and かどうか. However, when the issue is an open question (when/where/what), only か can used.

• Use either for yes/no issues:
  明日あした、雨あめが降ふるか（どうか）わかりますか。 = Do you know if it will rain tomorrow?
• Use only か for open questions (when/where/what/who/which/why/how):
  いつ／どこで／だれが／何を／どうして／どう + (short) + か
  • OK: どこで会あうかは、後あとで決きめましょう。 = We’ll decide where to meet later.
  • NG: どこで会うかどうかは….
• If you want an explicit “not,” you can say V か V-ないか (more explicit/formal):
  行いくか行かないか考かんがえています。= I’m thinking about whether to go or not.

4. Typical Verb Partners (sentence endings)

You’ll most often see embedded questions with these verbs/phrases:

• わかります (understand)
• 知しっています (know)
• 覚おぼえています (remember)
• 決きめます (decide)
• 調しらべます (look up / check)

5. Examples You’ll Actually Say

明日あした、雪ゆきが降ふるかどうか、まだわかりません。
I don’t know whether it will snow tomorrow.

その店みせが今日きょう 開あいているか、電話でんわで聞ききます。
I’ll call and ask if the shop is open today.

いつ遊園地ゆうえんちに行いったか、覚おぼえていますか。
Do you remember when you last went to an amusement park?

ゆうきさんとゆうこさんが付つき合あっているかどうか、知しりません。
I don’t know whether Yuki and Yuko are dating.

日本にほんに住すむかどうか、今年中ことしじゅうに決きめます。
I’ll decide whether to live in Japan within this year.

週末しゅうまつは晴はれるかどうか、知しっていますか。
Do you know if it will be sunny this weekend?

6. Particle Tricks (を / は with かどうか)

Treat [ … かどうか ] like a noun clause:

• [ … かどうか ] を 調べます／考えます。
  電車でんしゃが東京駅とうきょうえきに止とまるかどうかを調しらべます。 = I will check whether the train stops at Tokyo Station.
• [ … かどうか ] は まだわかりません。
  そのパーティーに参加さんかするかどうかは、まだわかりません。 = I’m not sure yet whether I’ll attend that party.

7. Practice Time!

You are wondering about the following. Express them using ～かどうかわかりません.

8. Common Mistakes

9. FAQ

Conclusion

You can now:

• ✅ Embed questions with (short) + か and say whether/if with (short) + かどうか
• ✅ Keep everything in short form before か／かどうか—even in polite sentences
• ✅ Choose か for open questions, and か or かどうか for yes/no issues
• ✅ Use noun-clause tricks with は／を to say what you’ll check, decide, or don’t know

Practice by turning five real questions from your day into embedded questions. The more you wrap questions inside bigger sentences, the more natural your Japanese will sound!