Japanese Verb Groups Explained: U-verbs, Ru-verbs, and Irregular Verbs (Complete Guide)

You sit down to write your first Japanese sentence about eating lunch. You know the word 食べる（たべる）means “to eat.” But how do you say “I ate”? Or “I didn’t eat”? Suddenly you realise the answer depends on something you were not taught first: which verb group does 食べる belong to?

Japanese verbs fall into three groups — Godan (Group 1), Ichidan (Group 2), and a tiny set of irregulars (Group 3). The group a verb belongs to determines every conjugation you will ever need: negative, past tense, て-form, potential, passive, causative, and more. Get this foundation right once, and the entire grammar system clicks into place.

At a Glance: The Three Verb Groups

Why Verb Groups Matter

In English, most verbs form their past tense by adding “-ed,” and negatives use the word “don’t.” Japanese works differently: the ending of the verb itself changes, and the pattern of those changes depends entirely on which group the verb belongs to.

Here is a side-by-side comparison using one verb from each group so you can see the difference clearly:

Notice how consistently different the patterns are. Group 2 (食べる) simply drops る and adds the suffix — clean and uniform. Group 1 (書く) shifts the final kana across five vowel rows. Group 3 follows its own unique path. The patterns make complete sense once you know them, but applying the wrong group’s rules to a verb produces errors every time.

Yuka

So I need to figure out which group a verb belongs to before I can conjugate it at all?

Rei

Exactly. Think of it like knowing whether a word is a noun or a verb before you try to use it in a sentence. Once you identify the group, the conjugation pattern is completely mechanical — no guessing needed.

Group 2: Ichidan Verbs (一段動詞)

Let us start with Group 2 because its identification rule is the simplest and its conjugation pattern is the most uniform. Ichidan（一段）means “one level” in Japanese — a reference to the fact that the verb stem stays on a single vowel level no matter which form you build. You drop る and add the ending. That is the whole rule.

How to Identify Group 2 Verbs

A verb is almost certainly Group 2 if both conditions are true:

• It ends in る
• The sound directly before る is an e-row kana (え、け、せ、て、ね、へ、め、れ、べ…) or an i-row kana (い、き、し、ち、に、ひ、み、り、ぎ、じ、び、ぴ…)

In practical terms: if you romanise the verb and it ends in -eru or -iru, it is probably ichidan. The caveat “probably” exists because a small set of common godan verbs also happen to end in -eru or -iru — those exceptions are covered in detail in the next section.

Common Group 2 Verbs

Group 2 Conjugation Table

The stem is formed by dropping る. Every suffix attaches directly to the stem — no sound changes, no special rules.

The uniformity here is the real advantage of Group 2 verbs. Once you have memorised that a verb is ichidan, conjugating it becomes a mechanical process of dropping る and attaching the correct suffix.

Group 1: Godan Verbs (五段動詞)

Godan（五段）means “five levels” — a reference to the fact that the verb’s final kana shifts across all five vowel rows (a, i, u, e, o) of the Japanese kana chart when you conjugate it. This makes godan verbs slightly more complex than ichidan verbs, but the system is completely rule-governed once you understand it.

How to Identify Group 1 Verbs

A verb is Group 1 if any of the following is true:

• It ends in any う-row kana other than る — that is, it ends in く、ぐ、す、つ、ぬ、ぶ、む、or う
• It ends in る, but the sound before る is an a-row, u-row, or o-row kana (for example: か→る, く→る, こ→る)
• It ends in る with an e or i sound before it, but is one of the common exceptions (see Section 5 below)

The Five-Row Conjugation System

Using 書く（かく, to write）as a model, here is how the final kana shifts across the five vowel rows:

て-form and Past Tense: Sound-Change Rules by Ending

The て-form and た-form (past) of Group 1 verbs involve sound changes that depend on the verb’s final kana. This is the conjugation rule learners most need to memorise for Group 1.

One exception to note: 行く（いく, to go）ends in く, so you might expect its て-form to be 行いて. It is not — the correct form is 行って. This is the only verb in the く group that behaves this way. Everything else about 行く follows normal godan rules.

20+ Common Godan Verbs

The “Looks Like Ichidan But Is Godan” Trap

This is the single greatest source of conjugation errors for beginners and intermediate learners alike. A set of common verbs end in -eru or -iru — the e/i + る pattern that normally signals Group 2 — but they are actually Group 1 godan verbs. You cannot identify them from the pronunciation alone. You have to memorise them.

Yuka

Wait — 帰る ends in -eru. By the e-row rule, shouldn’t it be ichidan?

Rei

You are right that the rule points that way — but 帰る is one of the classic exceptions. The e-row and i-row rule is extremely reliable, covering the vast majority of verbs. This handful of exceptions just needs to be memorised as a list, and most of them come up constantly in everyday Japanese, so you will learn them quickly through exposure.

The Most Important Exceptions to Memorise

Memory Tricks

• The movement cluster: 走る (run), 入る (enter), 帰る (return) are all about physical movement and are all godan. Group them mentally.
• 切る vs 着る: Both read as きる, but 切る (cut) is godan and 着る (wear) is ichidan. Remember: you put on clothes smoothly — ichidan, smooth and regular. You cut things with force — godan, five rows of change.
• The ない-form test: Form the negative of any uncertain る-ending verb. If the kana before ない is in the a-row (ら、か、さ…), the verb is godan. If it is in the e-row (れ、け、せ…) or remains in the i-row (き、し…), the verb is ichidan. Example: 帰る → 帰らない (a-row = godan). 食べる → 食べない (e-row = ichidan).
• When genuinely unsure: Check Jisho.org. Godan verbs are labelled v5k, v5g, v5s, v5t, v5n, v5b, v5m, v5u, or v5r. Ichidan verbs are labelled v1.

Group 3: The Two Irregular Verbs

Good news: Group 3 has exactly two members. Somewhat inconvenient news: those two members are among the most frequently used verbs in Japanese. You will encounter them every single day.

する — to do

来る（くる）— to come

Notice that 来る shifts its reading between く (dictionary form) and き or こ (other forms). The kanji 来 stays fixed, but the reading changes — a clear sign of its irregular nature.

Compound Verbs with する

Japanese allows you to attach する to a large number of nouns — especially nouns of Chinese or Western origin — to create verbs. Every one of these compound verbs conjugates exactly like する itself.

Yuka

So when I learn a new noun like 予約（よやく）I can just add する and instantly have a verb — and I already know all of its conjugations?

Rei

Exactly. That is one of the biggest vocabulary multipliers in all of Japanese. Every する compound gives you a verb for free. And since Japanese has hundreds of these — including many katakana loanword + する combinations — this pattern alone can add dozens of useful verbs to your active vocabulary very quickly.

Common Mistakes and How to Avoid Them

Mistake 1: Applying Godan て-form Rules to Ichidan Verbs

Learners who have just memorised the godan て-form sound-change table sometimes try to apply those rules to ichidan verbs:

Mistake 2: Treating Godan Exceptions as Ichidan

The reverse error — using ichidan rules on the common godan exceptions — is equally frequent:

Mistake 3: Applying Godan Rules to する Compounds

Some learners see 勉強する and, noticing that する ends in る (a godan ending), try to conjugate it like a godan る-verb:

する is Group 3 — fully irregular. No godan or ichidan rule applies to it.

Mistake 4: Using 知る to Mean “I Know”

知る（しる）means “to come to know” — the moment of learning something. The ongoing state of knowing is expressed with the ている construction: 知っている（しっている）. Saying 私は知る（わたしはしる）for “I know” sounds unnatural in most contexts. Use 知っています（しっています）instead, and 知りません（しりません）for “I don’t know.”

Decision Flowchart: Which Group Is This Verb?

Use this flowchart whenever you encounter an unfamiliar verb in its dictionary form.

START: You have a verb in dictionary form.
        |
        v
Is it する or 来る (or a compound ending in する)?
  YES ---> Group 3 (Irregular). Use the する / 来る conjugation tables.
  NO  ---> Continue
        |
        v
Does the dictionary form end in る?
  NO  ---> Group 1 (Godan).
           Apply sound-change rules based on the final kana
           (く→いて, む→んで, つ→って, す→して, etc.)
  YES ---> Continue
        |
        v
What is the sound immediately BEFORE る?

  a-row kana (か、さ、た、な、は、ま、ら…)?
    ---> Group 1 (Godan). Always. No exceptions.

  u-row kana (く、す、つ、ぬ、ふ、む、ゆ、る…)?
    ---> Group 1 (Godan). Always. No exceptions.

  o-row kana (こ、そ、と、の、ほ、も、よ、ろ…)?
    ---> Group 1 (Godan). Always. No exceptions.

  e-row kana (え、け、せ、て、ね、へ、め、れ、べ…)?
    ---> PROBABLY Group 2 (Ichidan).
         But check the exception list:
         帰る、蹴る、喋る、滑る、減る…
         If YES (exception) ---> Group 1 (Godan)
         If NO              ---> Group 2 (Ichidan) confirmed

  i-row kana (い、き、し、ち、に、ひ、み、り、ぎ、じ…)?
    ---> PROBABLY Group 2 (Ichidan).
         But check the exception list:
         切る、走る、入る、知る、要る、握る、限る…
         If YES (exception) ---> Group 1 (Godan)
         If NO              ---> Group 2 (Ichidan) confirmed

Still unsure? Look up the verb on Jisho.org:
  v1  = Group 2 (Ichidan)
  v5* = Group 1 (Godan)
  vs  = する compound (Group 3)

Quick Quiz

Test your understanding. For each verb, identify the group and form the requested conjugation.

Q1. 飲む（のむ, to drink）— What group? Form the て-form.

▼ Group 1 (Godan). Ends in む → んで: 飲んで

Q2. 起きる（おきる, to wake up）— What group? Form the negative.

▼ Group 2 (Ichidan). drop る, add ない: 起きない

Q3. 帰る（かえる, to return home）— What group? Form the past tense.

▼ Group 1 (Godan) — exception! る (godan) → った: 帰った

Q4. 練習する（れんしゅうする, to practise）— What group? Form the て-form.

▼ Group 3 (Irregular). する → して: 練習して

Q5. 走る（はしる, to run）— What group? Form the negative. [Caution: this one fools many learners.]

▼ Group 1 (Godan) — exception! a-row + ない: 走らない (NOT 走ない)

Q6. 調べる（しらべる, to look up / investigate）— What group? Form the potential form.

▼ Group 2 (Ichidan). drop る, add られる: 調べられる

Summary Table

Which verb group trips you up the most? Share a tricky verb in the comments — especially if you found an -iru or -eru verb that fooled you!

Want to practise verb conjugation with a native speaker? Find a Japanese tutor on italki — drilling verb groups in real conversation is the fastest way to make these patterns automatic.

Keep Learning

Now that you know the three verb groups, apply the knowledge to these essential conjugation patterns:

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