Before you can conjugate a single Japanese verb, you need to get one thing right: classification. Classify it wrong, and every conjugation that follows will be wrong too. The good news? Japanese verb classification follows clear, learnable rules.
Dictionary Form: Where It All Starts
Japanese verbs have many forms (ます form, ない form, て form...), but they all derive from the dictionary form (辞書形 / じしょけい), also called the plain form or 原形.
Every dictionary form shares one trait: the last kana is always in the う-row.
| Verb | Reading | Last sound |
|---|---|---|
| 読む | よむ | む (う-row) |
| 食べる | たべる | る (う-row) |
| 書く | かく | く (う-row) |
| 来る | くる | る (う-row) |
No matter what type of verb it is, the dictionary form always ends in an う-row kana. No exceptions.
The Five Categories
Japanese verbs fall into 5 categories (some textbooks use 3 groups — same idea):
| Category | Alias | Examples |
|---|---|---|
| Godan (五段) | Group I | 読む, 書く, 話す |
| Kami-ichidan (上一段) | Group II | 起きる, 見る |
| Shimo-ichidan (下一段) | Group II | 食べる, 出る |
| Ka-gyou irregular (カ変) | Group III | 来る (only one) |
| Sa-gyou irregular (サ変) | Group III | する (only one) |
Textbooks like Minna no Nihongo merge kami-ichidan and shimo-ichidan into "Group II" and both irregulars into "Group III." The logic is identical — just different granularity.
How to Identify Godan Verbs
Godan verbs are the most common type. Here's the decision process:
Rule 1: Last kana is NOT る → definitely godan
| Verb | Last kana | Verdict |
|---|---|---|
| 読む | む | Godan |
| 書く | く | Godan |
| 話す | す | Godan |
| 会う | う | Godan |
If it doesn't end in る, don't even think twice.
Rule 2: One kanji + one kana → almost always godan
| Verb | Structure | Verdict |
|---|---|---|
| 読む | 読 + む | Godan |
| 書く | 書 + く | Godan |
| 乗る | 乗 + る | Godan |
There are 12 exceptions (listed below), but this rule works for the vast majority of cases.
Rule 3: Ends in る, but the kana before る is NOT in the い-row or え-row → godan
| Verb | Kana before る | Row | Verdict |
|---|---|---|---|
| 終わる | わ | あ-row | Godan |
| 始まる | ま | あ-row | Godan |
| 送る | く | う-row | Godan |
How to Identify Kami-ichidan (Upper Ichidan)
Features:
- Last kana is る
- The kana before る is in the い-row (き, し, ち, に, ひ, み, り...)
| Verb | Before る | い-row? | Verdict |
|---|---|---|---|
| 起きる | き | Yes | Kami-ichidan |
| 落ちる | ち | Yes | Kami-ichidan |
| 降りる | り | Yes | Kami-ichidan |
Why "upper"? Because い is one row above う in the kana chart (あいうえお).
How to Identify Shimo-ichidan (Lower Ichidan)
Features:
- Last kana is る
- The kana before る is in the え-row (け, せ, て, ね, へ, め, れ...)
| Verb | Before る | え-row? | Verdict |
|---|---|---|---|
| 食べる | べ | Yes | Shimo-ichidan |
| 出かける | け | Yes | Shimo-ichidan |
| あげる | げ | Yes | Shimo-ichidan |
え is one row below う (あいうえお), hence "lower."
The Same-Sound Trap
帰る (かえる) and 変える (かえる) are pronounced identically but belong to different categories:
| Verb | Structure | Before る | Verdict |
|---|---|---|---|
| 帰る | 帰 + る (1 kanji + 1 kana) | — | Godan |
| 変える | 変 + える (1 kanji + 2 kana) | え | Shimo-ichidan |
Always look at the kanji-kana structure, not just the pronunciation.
The 12 Exception Verbs
These 12 verbs look like godan (one kanji + one kana) but are actually ichidan. You must memorize them.
8 Kami-ichidan Exceptions (い-row before る)
| Verb | Reading | Meaning | Frequency |
|---|---|---|---|
| いる | いる | to exist (animate) | Very high |
| 着る | きる | to wear | High |
| 似る | にる | to resemble | High |
| 煮る | にる | to boil/cook | Medium |
| 見る | みる | to see/look | Very high |
| 射る | いる | to shoot | Low |
| 干る | ひる | to dry | Low |
| 嚙る | かじる | to gnaw | Low |
4 Shimo-ichidan Exceptions (え-row before る)
| Verb | Reading | Meaning | Frequency |
|---|---|---|---|
| 出る | でる | to go out | Very high |
| 寝る | ねる | to sleep | Very high |
| 経る | へる | to pass through | Low |
| 蹴る | ける | to kick | Medium |
Priority: memorize いる, 見る, 着る, 似る, 出る, 寝る first — they appear constantly in exams and daily conversation.
Ka-gyou and Sa-gyou Irregular Verbs
These two "special players" each have only one word:
| Category | Verb | Key trait |
|---|---|---|
| Ka-gyou | 来る (くる) | Completely irregular conjugation |
| Sa-gyou | する | Universal verb: noun + する = verb |
する is incredibly productive — any noun can become a verb by adding する:
| Noun | + する | Meaning |
|---|---|---|
| 勉強 | 勉強する | to study |
| 予習 | 予習する | to preview |
| プレゼント | プレゼントする | to give a present |
Classification Flowchart
When you see a verb in dictionary form, follow this order:
- Is it 来る? → Ka-gyou irregular
- Contains する? → Sa-gyou irregular
- Last kana is NOT る? → Godan
- Last kana is る + one kanji + one kana → check the 12 exceptions; if not listed, godan
- Last kana is る + kana before it is in い-row → Kami-ichidan
- Last kana is る + kana before it is in え-row → Shimo-ichidan
- Last kana is る + kana before it is neither い-row nor え-row → Godan
Summary
- Dictionary form always ends in an う-row kana
- Godan verbs are the most common; if it doesn't end in る, it's godan
- Kami-ichidan: ends in る + い-row kana before it
- Shimo-ichidan: ends in る + え-row kana before it
- 12 exceptions must be memorized — especially いる, 見る, 着る, 出る, 寝る
- Ka-gyou has only 来る; Sa-gyou has only する (and its compounds)
Practice Questions
Q1. Classify these verbs: 泳ぐ, 起きる, する
Show answer
- 泳ぐ: last kana is ぐ (not る) → Godan
- 起きる: last kana is る, kana before it is き (い-row) → Kami-ichidan
- する → Sa-gyou irregular
Q2. Is 帰る (かえる) godan or shimo-ichidan? Why?
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Godan. Although it ends in る, 帰る has a one-kanji-one-kana structure and is not on the 12 exceptions list.
Don't confuse it with 変える (shimo-ichidan) — 変える has two kana after the kanji (え + る), and え is in the え-row.
Q3. Why isn't 寝る godan even though it's one kanji + one kana?
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Because 寝る is one of the 12 exceptions. Despite looking like a godan verb (one kanji + one kana), it's actually a shimo-ichidan verb (the ね before る is in the え-row). These exceptions must be memorized.