Definition:
Japanese verb conjugation is the systematic modification of verb stems to express tense (plain past/non-past), formality (plain vs. polite), mood (negative, volitional, conditional, potential, passive, causative), and more. Unlike English, where most conjugation is lexical (go/went) or uses auxiliaries (will go, has gone), Japanese conjugation is almost entirely suffixal — modifications are made by changing the ending attached to a consistent verb stem.
The Three Verb Groups
Japanese verbs are divided into three groups based on their conjugation patterns:
Group 1: Godan verbs (五段動詞) — “u-verbs”
Regular verbs ending in -u (in dictionary form) that use five different stem forms in conjugation. The consonant before the -u changes predictably.
Examples: 書く (kaku — to write), 飲む (nomu — to drink), 話す (hanasu — to speak), 買う (kau — to buy)
Key conjugations:
| Form | 書く (kaku) |
|---|---|
| Dictionary form | 書く |
| Masu form (polite) | 書きます |
| Nai form (negative) | 書かない |
| Te form | 書いて |
| Ta form (past) | 書いた |
Group 2: Ichidan verbs (一段動詞) — “ru-verbs”
Verbs ending in -iru or -eru whose stem does not change; only the final -ru is replaced by conjugation endings.
Examples: 食べる (taberu — to eat), 見る (miru — to see), 起きる (okiru — to wake up)
Key conjugations:
| Form | 食べる (taberu) |
|---|---|
| Dictionary form | 食べる |
| Masu form (polite) | 食べます |
| Nai form (negative) | 食べない |
| Te form | 食べて |
| Ta form (past) | 食べた |
Group 3: Irregular verbs
Only two verbs: する (suru — to do) and 来る (kuru — to come). These conjugate irregularly and must be memorized individually.
| Form | する (suru) | 来る (kuru) |
|---|---|---|
| Masu form | します | 来ます |
| Nai form | しない | 来ない |
| Te form | して | 来て |
| Ta form | した | 来た |
Key Conjugation Forms
Polite form (-masu / -masen):
The default spoken formal register. The masu-stem (or i-form) is the foundation for many polite conjugations.
- 飲みます (nomimasu) — drink (polite, present/future)
- 飲みません (nomimasen) — don’t drink (polite, negative)
- 飲みました (nomimashita) — drank (polite, past)
Te-form:
See the Te-Form entry. The te-form is used to connect clauses, form the progressive, make requests, and as the base for numerous compound forms.
Plain form (dictionary / ta / nai / nakatta):
Used in casual speech, subordinate clauses, and before certain grammatical endings.
Conditional forms (-ba / -tara):
- -ba form: Expresses hypothetical or general conditions: 食べれば (tabereba — “if [you] eat”)
- -tara form: Expresses sequential events or real conditions: 食べたら (tabetara — “if/when you eat / after eating”)
Potential form (-eru / -rareru):
See the Potential Form entry. Expresses ability.
- 食べられる (taberareru) — can eat
- 飲める (nomeru) — can drink
Passive and causative forms:
See the Passive Form and Causative Form entries.
The U-Verb / Ru-Verb Ambiguity
Several verbs ending in -iru or -eru are actually Group 1 (godan/u-verbs), not Group 2 — a common source of confusion:
- 帰る (kaeru — to return) → godan: te-form is 帰って, not 帰て
- 走る (hashiru — to run) → godan: te-form is 走って
- 知る (shiru — to know) → godan: te-form is 知って
Distinguishing these by pattern recognition requires vocabulary depth; explicit study of verb groups prevents systematic errors.
History
Japanese verb conjugation has been described and taught systematically since the Heian period (794–1185), when the formal study of classical Japanese (bungo) grammar became established in literary education. The traditional Japanese grammatical analysis (kokubunpo) categorized verbs by their conjugation types (katsuyokei: renyokei, shuushikei, etc.) using rows of the kana table as the organizing framework — a system that remains the basis for the modern ichidan/godan categorization. From the Meiji era (late 19th century), Japanese grammar was systematized for national education standards. Modern Japanese language pedagogy for L2 learners adapts the traditional conjugation analysis into the “plain form”-based approach used in most contemporary textbooks, where the dictionary form (basic form) serves as the citation form from which all conjugated forms are derived.
Common Misconceptions
“All Japanese verbs conjugate the same way.” Japanese divides verbs into two major classes (ichidan/group 1 “ru-verbs” and godan/group 2 “u-verbs”) plus two irregular verbs (suru — to do, kuru — to come). Each class follows a different conjugation pattern: ichidan verbs simply drop -ru and add the suffix; godan verbs show consonant changes in the stem followed by different suffix types. Learning which group a verb belongs to is prerequisite to accurately conjugating it — the dictionary form alone does not always reveal the verb class.
“Japanese verb conjugation only expresses tense.” Japanese verbs conjugate to express tense (past: -ta/-mashita), politeness level (plain form vs. masu-form), aspect and modality (-te iru for ongoing states, -te shimau for completion/regret), conditionality (-ba, -tara, -nara), potential (-rareru/-reru), passive (-rareru), causative (-saseru), and various discourse and pragmatic functions through sentence-final forms. Japanese verb morphology expresses a much richer range of grammatical information than English tense-aspect morphology alone.
Criticisms
Japanese verb conjugation instruction has been criticized for the fragmentation of the conjugation paradigm into separate grammar points taught one-by-one across multiple textbook units, which hinders learners from developing an integrated understanding of the verb morphology system as a whole. Teaching forms in isolation (te-form in chapter 6, potential in chapter 12, passive in chapter 15) without connecting them to the underlying paradigm makes the system appear more arbitrary and harder to retain than it is. Communicative approaches that minimize explicit grammar instruction have been challenged for under-preparing learners for the morphological complexity of authentic Japanese text.
Social Media Sentiment
Japanese verb conjugation is essential beginner-to-intermediate Japanese grammar content and one of the most resource-rich areas of the online Japanese learning community. Charts, mnemonics, and learning resources for the verb conjugation paradigm are widely shared. The community strongly endorses early mastery of the ichidan/godan distinction and the core conjugation forms (te-form, ta-form, nai-form, potential, passive) as prerequisite for authentic text comprehension. Advanced community discussions address the complexity of conditional forms (tara, ba, nara, to) and how to select among them appropriately.
Last updated: 2026-04
Practical Application
For Japanese learners:
- Master the te-form transformation early — it unlocks a large portion of intermediate grammar
- Drill the godan consonant changes systematically: k?i, g?i, s?shi, t?tte, n?nde, m?nde, r?tte, w?tte, b?nde
- Use Bunpro and grammar textbooks to drill the forms; spaced repetition for verb conjugations is highly effective
- When you encounter a new verb, immediately check which group it belongs to — making this a habit prevents long-term misclassification
- Sakubo
Related Terms
See Also
Research
- Makino, S., & Tsutsui, M. (1986). A Dictionary of Basic Japanese Grammar. The Japan Times. [Summary: The standard reference grammar for Japanese learners — comprehensive descriptions of all major conjugation patterns with example sentences and usage notes; remains one of the most trusted English-language Japanese grammar resources.]
- Jorden, E. H., & Noda, M. (1987). Japanese: The Spoken Language. Yale University Press. [Summary: Influential academic Japanese teaching grammar that systematizes verb group classification and conjugation within a pedagogically organized framework; particularly strong on the morphological analysis of verbal and adjectival inflection.]