How Conjugation Works
活用の基礎 · Lesson 1
Learn the basics: dictionary form, why verb type matters, and how Japanese verbs change by ending instead of person or number.
In Japanese, verbs don't change by person (no I/you/he forms) or number. Only the ending changes for present/past, polite/casual, positive/negative, and more.
The dictionary form (辞書形) is the "to do" form e.g. 書く (to write), 食べる (to eat), 見る (to see). Every other form is built from it. Your first step is always: what type of verb is this?
You can combine forms (polite + negative, polite + past, etc.). For example with 書く: 書きます (polite), 書きません (polite negative), 書きました (polite past), 書きませんでした (polite negative past). The Complex forms lesson covers these in detail.
The two irregular verbs are する (to do) often used with a noun, e.g. 勉強する (to study)—and 来る (to come). Memorize their conjugations; they don't follow Godan or Ichidan rules.
| Group | Name | How to recognize |
|---|---|---|
| Godan | 五段 | Most common. End in う, く, ぐ, す, つ, ぬ, ぶ, む, or る (but not -いる/-える like 食べる). |
| Ichidan | 一段 | End in -る with い or え just before it (e.g. 食べる, 見る). Easier to conjugate. |
| Irregular | — | Only する (to do) and 来る (to come). Memorize these. |
How Godan verbs change: the vowel step
Godan verbs are "five-step" because the last vowel steps through あ・い・う・え・お depending on the form. Example: あう (to meet):
Dictionary: "to meet"
Stem + う-vowel
Key: The stem (あ) stays the same; only the final vowel changes: あわ・あい・あう・あえ・あお
In the next lesson we'll see full conjugation tables for each verb group.
Example sentences
Same meaning, different forms (dictionary vs polite):
本を読む。 / 本を読みます。
I read a book. (plain / polite)
水を飲む。 / 水を飲みます。
I drink water. (plain / polite)
勉強する。 / 勉強します。
I study. (plain / polite)
Video Explanation
We recommend watching this comprehensive explanation by Jouzu Juls for additional insights.
You know the basics: dictionary form, endings, and that verb type matters.
Ready for the next step? Continue to Verb Groups below to see Godan, Ichidan, and irregular verbs. You're building a solid foundation. 頑張って！