Introduction
Most Japanese verbs follow regular patterns — either as ru-verbs or u-verbs. But there are a couple of important exceptions you absolutely need to know:
する (to do) and くる (to come).
These are called irregular verbs, and while they don’t follow the usual rules, they’re incredibly useful and common in daily conversation.
In this article, you’ll learn:
✔ How to conjugate する and くる into polite forms
✔ Example sentences using these verbs naturally
✔ A list of common “する-verbs” you’ll see everywhere
✔ How to practice and avoid common mistakes
✔ An FAQ section with bonus tips
Let’s tackle these powerful verbs!
1. What Are Irregular Verbs in Japanese?
Japanese has two main irregular verbs:
| Verb | Meaning |
|---|---|
| する | to do |
| 来る（くる） | to come |
They don’t follow the rules of ru-verbs or u-verbs. You simply need to memorize their conjugation patterns — but don’t worry, they’re used so often you’ll remember them fast!
2. How to Conjugate する and くる
Polite Present Forms
| Dictionary | Polite | Polite Negative |
|---|---|---|
| する | します | しません |
| くる | きます | きません |
Note: The stem of くる changes to き in the polite form — it’s unique!
3. Real-Life Sentence Examples
| Japanese | Romaji | English |
|---|---|---|
| 日本語（にほんご）の べんきょうを します。 | nihongo no benkyou o shimasu | I study Japanese. |
| スポーツをしません。 | supootsu o shimasen | I don’t play sports. |
| あした、先生（せんせい）が きます。 | ashita, sensei ga kimasu | The teacher will come tomorrow. |
| ともだちが うち に きます。 | tomodachi ga uchi ni kimasu | A friend is coming over. |
4. Common “する-Verbs” You Should Know
The verb する is super flexible! It attaches to many nouns to form compound verbs.
| Noun + する | Meaning |
|---|---|
| べんきょう + する → べんきょうする | to study |
| れんしゅう + する → れんしゅうする | to practice |
| よやく + する → よやくする | to make a reservation |
| そうじ + する → そうじする | to clean |
| しごと + する → しごとする | to work |
Conjugation is just like する:
- よやく します
- れんしゅう しません
- そうじ しました（past tense）
5. Practice Time: Try Conjugating These!
| Verb | Polite | Polite Negative |
|---|---|---|
| する（to do） | します | しません |
| べんきょうする（to study） | べんきょうします | べんきょうしません |
| くる（to come） | きます | きません |
| そうじする（to clean） | そうじします | そうじしません |
✅ Try saying these aloud or writing them in your notebook!
6. FAQ – Frequently Asked Questions
- QIs くる the only verb that uses “きます”?
- A
It’s the polite form of くる. Don’t confuse it with 着ます（きます）, which means “to wear.”
- QCan I use する with any noun?
- A
Not all nouns, but many activity-related nouns can be combined with する.
- QAre there irregular verbs beyond する and くる?
- A
These are the only two truly irregular verbs. Some verbs like いく have irregular forms in specific tenses (like いって), but they’re still classified as regular u-verbs.
7. Conclusion: Power Up Your Japanese with する and くる!
Irregular verbs may sound intimidating, but in Japanese, there are just two to remember — and both are super useful!
By mastering する and くる, you’ll open the door to expressing actions, movement, and tons of useful daily expressions.
🎯 Your next step: Try using べんきょうする and きます in a few example sentences of your own!
Want to improve your Japanese with real conversations?
Our native Japanese instructors at gokigen japanese can help you perfect your pronunciation and learn real-life usage.
Whether you’re completely new to Japanese or looking to refine your skills, book a one-on-one session.
