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 is the "to do" form e.g. 書かく (to write), 食たべる (to eat), 見みる (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 書かく: 書かきます (polite), 書かきません (polite negative), 書かきました (polite past), 書かきませんでした (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. 勉強べんきょうする (to study)—and 来くる (to come). Memorize their conjugations; they don't follow Godan or Ichidan rules.

Group	Name	How to recognize
Godan	五ご段だん	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	一いち段だん	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 来くる (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):

あう

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):

本ほんを読よむ。 / 本ほんを読よみます。

I read a book. (plain / polite)

水みずを飲のむ。 / 水みずを飲のみます。

I drink water. (plain / polite)

勉強べんきょうする。 / 勉強べんきょうします。

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. 頑張がんばって！