:Japanese godan and ichidan verbs

Categories are important when conjugating Japanese verbs, since conjugation patterns vary according to the verb's category. For example, {{nihongo krt||切る|kiru}} and {{nihongo krt||見る|miru}} belong to different verb categories (quinquegrade and unigrade, respectively) and therefore follow different conjugation patterns. Most Japanese verbs are allocated into two categories:

1. {{nihongo|Quinquegrade,{{sfnp|Iwasaki|2001|p=242}}{{cite journal|url=https://nichibun.repo.nii.ac.jp/record/5298/files/niso_031__479__463_476__479_492.pdf|last=Serafim|first=Leon A.|year=2003|title=When and from where did the Japonic language enter the Ryukyus? -A critical comparison of language, archaeology, and history|journal=Perspectives on the Origins of the Japanese Language|volume=31|p=473}}{{sfnp|Aoki|2024|p=282}} quinquigrade,{{sfnp|Frellesvig|2010|p=392}}{{cite journal|last=de Chene|first=Brent|year=2016|title=Description and explanation in morphophonology: The case of Japanese verb inflection|journal=Journal of East Asian Linguistics|volume=25|pp=37-80|url=https://www.academia.edu/download/88264337/2016_D_E_JEAL_.pdf}}{{sfnp|Vance|2022|p=511}} quinquagrade{{cite book|p=272|chapter=Modern Japanese|title=The Languages of Japan and Korea|date=25 June 2012|publisher=Routledge|first=Nicolas|last=Tranter|first2=Mika|last2=Kizu|editor-first=Nicolas|editor-last=Tranter|isbn=978-0-415-46287-7}} or pentagrade{{cite journal|last=Matsuda|first=Kenjirō|year=2013|title=On the internal factors constraining the changes of sa-hen verbs into go-dan and kamiichi-dan verbs in the current Japanese law|script-title=ja:現行法令におけるサ変動詞五段化・上一段化現象の言語内的要因|journal=Theoretical and applied linguistics at Kobe Shoin: {{lang|ja|トークス}}|volume=16|p=51|language=ja|url=https://shoin.repo.nii.ac.jp/record/1145/files/TALKS2013matsuda.pdf}}{{cite journal|first=Max|last=Monson|first2=Matthew L.|last2=Guay|year=2024|title=A Hitchhiker’s Guide to Standard Japanese Nominal and Verbal Morphology|script-journal=ja:流通經濟大學論集|volume=59|number=1|p=34|url=https://rku.repo.nii.ac.jp/record/2000207/files/%E8%AB%96%E9%9B%86224%E5%8F%B7%E3%82%B0%E3%82%A8%E3%82%A4.pdf}} verbs|五段動詞|godan-dōshi|chapter=Lyman’s Rendaku Research from a Modern Perspective}}
2. {{nihongo|Unigrade{{sfnp|Verbeck|1887|p=13}}{{cite book|year=1928|title=An Historical Grammar of Japanese|first=George Bailey|last=Sansom|authorlink=George Sansom|location=Oxford|publisher=Clarendon Press|p=129}}{{cite book|p=35|year=1951|chapter=The Forms of the Verb|title=A Grammar of Formal Written Japanese|first=Winfred Philipp|last=Lehmann|authorlink=Winfred P. Lehmann|first2=Lloyd|last2=Faust|publisher=Harvard University Press|location=Cambridge, Massachusetts|series=Harvard–Yenching Institute Studies}}{{sfnp|Iwasaki|2001|p=240}}{{sfnp|p=241|Miyagawa|2019}} or monograde{{sfnp|Frellesvig|2010|p=xxii}}{{sfnp|p=215|Miyagawa|2019}}{{sfnp|Vovin|2020|p=570}}{{sfnp|Vance|2022|p=511}}{{sfnp|Aoki|2024|p=269}} verbs|一段動詞|ichidan-dōshi}}

Statistically, there are about twice as many quinquegrade verbs{{cite web|title=JMdictDB - Quinquegrade Verbs - 7434 Search results|url=http://www.edrdg.org/jmdictdb/cgi-bin/srchres.py?svc=jmdict&s1=1&y1=3&t1=&s2=1&y2=1&t2=&s3=1&y3=1&t3=&idtyp=seq&idval=&src=1&stat=2&appr=appr&nfcmp=&nfval=&pos=30&pos=31&pos=32&pos=33&pos=34&pos=35&pos=36&pos=37&pos=38&pos=39&pos=40&pos=41&pos=42&pos=43&snote=&snotem=0&smtr=&smtrm=0&ts0=&ts1=&refs=&refsm=0&cmts=&cmtsm=0&mt=0&grp=&search=Search|access-date=21 March 2021|website=www.edrdg.org}} than unigrade verbs.{{cite web|title=JMdictDB - Unigrade Verbs - 3733 Search results|url=http://www.edrdg.org/jmdictdb/cgi-bin/srchres.py?svc=jmdict&s1=1&y1=2&t1=&s2=1&y2=1&t2=&s3=1&y3=1&t3=&idtyp=seq&idval=&src=1&stat=2&appr=appr&appr=unappr&nfcmp=&nfval=&pos=28&pos=29&pos=49&snote=&snotem=0&smtr=&smtrm=0&ts0=&ts1=&refs=&refsm=0&cmts=&cmtsm=0&mt=0&grp=&search=Search|access-date=21 March 2021|website=www.edrdg.org}}

Classical Japanese had more verb groups, such as {{nihongo|bigrade{{sfnp|Verbeck|1887|p=12}}{{sfnp|Iwasaki|2001|p=240}}{{sfnp|Frellesvig|2010|pp=xxii–xxiii}}{{cite book|p=197|chapter=Old Japanese|title=The Languages of Japan and Korea|date=25 June 2012|publisher=Routledge|first=John R.|last=Bentley|editor-first=Nicolas|editor-last=Tranter|isbn=978-0-415-46287-7}}{{sfnp|p=241|Miyagawa|2019}}{{sfnp|Vovin|2020|p=449}}{{sfnp|Vance|2022|p=490}}{{sfnp|Aoki|2024|p=269}} verbs|二段動詞|nidan-dōshi}} and {{nihongo|quadrigrade{{sfnp|Verbeck|1887|p=12}}{{sfnp|Iwasaki|2001|p=240}}{{sfnp|Frellesvig|2010|p=xxii}}{{sfnp|p=241|Miyagawa|2019}}{{sfnp|Vovin|2020|p=449}}{{sfnp|Vance|2022|p=490}}{{cite book|p=282|chapter=Old Japanese writing and phonology|authorlink=J. Marshall Unger|first=James Marshall|last=Unger|editor-first=Bjarke|editor-last=Frellesvig|editor-first2=Satoshi|editor-last2=Kinsui|title=Handbook of Historical Japanese Linguistics|series=Handbooks of Japanese Language and Linguistics|publisher=De Gruyter|year=2024|isbn=978-1-61451-401-5}} verbs|四段動詞|yodan-dōshi}}, which are archaic in Modern Japanese.

The word grade in quinquegrade and unigrade is translated from {{nihongo||段|dan}}.{{efn|The most familiar use of this Japanese word in English contexts is for ranking in martial arts.}} In grammar, dan is a synonym for {{nihongo||列|retsu}}Daijirin and opposite to {{nihongo||行|gyō}}. The translations for dan/retsu and gyō vary, either of them can be translated as "row" or "column", but the distinction is simply that gyō is named after consonants, as {{nihongo|ka-row|か行|ka-gyō}}, while dan/retsu is named after vowels, as in {{nihongo|i-column|い烈|i-retsu}} or {{nihongo|i-grade|い段|i-dan}}. The {{nihongo|a-row|あ行|a-gyō}} consists the kana {{nihongo||あ|a}}, {{nihongo||い|i}}, {{nihongo||う|u}}, {{nihongo||え|e}}, {{nihongo||お|o}}, which differ only by vowels; while the {{nihongo|a-grade|あ段|a-dan}} consists of the kana {{nihongo||あ|a}}, {{nihongo||か|ka}}, {{nihongo||が|ga}}, {{nihongo||さ|sa}}, {{nihongo||ざ|za}}, {{nihongo||た|ta}}, {{nihongo||だ|da}}, {{nihongo||な|na}}, {{nihongo||は|ha}}, {{nihongo||ば|ba}}, {{nihongo||ぱ|pa}}, {{nihongo||ま|ma}}, {{nihongo||や|ya}}, {{nihongo||ら|ra}}, {{nihongo||わ|wa}}, which differ only by consonants.

The {{nihongo|quinquegrade|五段|godan}} class consists of verbs whose inflection forms make use of all five grades, or five vowels. For example, the inflection forms of the verb {{nihongo||書く|kaku|"to write; to draw", ka-row}} are {{nihongo||書か|kaka}}/{{nihongo||書こ|kako}}, {{nihongo||書き|kaki}}, {{nihongo||書く|kaku}}, and {{nihongo||書け|kake}}. These verbs developed from the earlier {{nihongo|quadrigrade|四段|yodan}} class, after a historical sound change that turned such form as {{nihongo||書かむ|kakamu}} into {{nihongo||書こう|kakō}} and resulted in an additional vowel (see Late Middle Japanese).

The {{nihongo|unigrade|一段|ichidan}} class consists of verbs that occupy only one grade, or one vowel. DictionariesNihon Kokugo DaijitenDaijisenKōjien may further divide this class into {{nihongo|"upper unigrade"|上一段|kamiichidan}}) if the vowel is the "upper" i, and {{nihongo|"lower unigrade"|下一段|shimoichidan}}){{sfnp|Frellesvig|2010|pp=xxii–xxiii}} if the vowel is the "lower" e. The verb {{nihongo||見る|miru|"to look", ma-row}}, whose inflection forms are {{nihongo||見|mi}}, {{nihongo||見る|miru}}, {{nihongo||見れ|mire}} and {{nihongo||見ろ|miro}}/{{nihongo||見よ|miyo}}, is an example of an "upper unigrade" verb, and the verb {{nihongo||得る|eru|"to earn", a-row}} is a "lower unigrade" verb. Some unigrade verbs evolved from earlier forms of bigrade verbs ({{nihongo|upper bigrade|上二段|kaminidan}} and {{nihongo|lower bigrade|下二段|shimonidan}}).

Dictionaries often list ancestral forms of modern verbs as well as their classes. Thus, the entry for kaku may include a note like {{lang|ja|（動カ五［四］）}}, which means "verb, ka-row, quinquegrade, formerly quadrigrade"); while the entry for {{nihongo||受ける|ukeru|"to take"}} may include {{lang|ja|（動カ下一）[文]カ下二 う・く}}, which means "verb, ka-row, lower unigrade, lower bigrade equivalent in Classical Japanese is {{nihongo||受く|uku}}".

Note that the choices of prefixes in these English terms by some authors are rather inconsistent: while mono- and penta- are Greek, uni-, bi-, quadri- and quinque- are Latin (see {{section link|Numeral prefix#Table of number prefixes in English}}). The word grade is actually Latin, not Greek in origin.{{cite web|url=https://www.merriam-webster.com/dictionary/grade#word-history|title=grade|website=Merriam-Webster}} While many authors use bigrade and quadrigrade consistently, they also use any combination of unigrade, monograde, quinquegrade, quinquigrade and pentagrade. Some dispense with {{nihongo|quinquegrade|五段|godan}} altogether and prefer only {{nihongo|quadrigrade|四段|yodan}}{{cite book|title=Handbook of Japanese Grammar|last=Henderson|first=Harold Gould|authorlink=Harold Gould Henderson|edition=revised|publisher=Houghton Mifflin Company|year=1948|pp=14–15, 22}} even for modern Japanese (see Godan vs yodan below). Plain English alternatives to "unigrade", "bigrade", "quadrigrade" and "quinquegrade" include "one-grade", "two-grade", "four-grade" and "five-grade";{{cite book|p=xiv|chapter=Introduction|title=An Unabridged Japanese-English Dictionary|location=Tōkyō|publisher=Sanseidō|editor-first=Francis|editor-last=Brinkley|editor-link=Francis Brinkley|editor-last2=Nanjō|editor-first2=Bun'yū|editor-link2=Nanjō Bun'yū|editor-last3=Iwasaki|editor-first3=Y.|editor-last4=Kakichi|editor-first4=Mitsuru|editor-link4=Kakichi Mitsukuri|editor-last5=Jinzō|editor-first5=Matsumura|editor-link5=Jinzō Matsumura}}{{cite book|title=Classical Japanese: A Grammar|last=Shirane|first=Haruo|year=2005|publisher=Columbia University Press|pp=2, 403|isbn=978-0-231-13524-5}} "one row", "two row" and "four row";{{cite book|title=A Grammar of Classical Japanese|last=Komai|first=Akira|year=1979|pp=20, 29, 34|chapter=動詞 {{under|Doosi}} "verbs"}} "one-step", "two-step", "four-step" and "five-step";{{cite book|title=Topics in Constraint-Based Grammar of Japanese|year=1999|p=127|chapter=An Overview of the JPSG Phonology|first=Michinao Francis|last=Matsui|editor-first=Gunji|editor-last=Takao|editor-first2=Kōichi|editor-last2=Hashida|publisher=Springer Science+Business Media Dordrecht|isbn=978-0-7923-5611-0}}{{efn|"Step" is another translation for dan.}} or "one-vowel", "two-vowel" and "four-vowel".

Some Western analyses refer to "quinquegrade" verbs as "consonant-stem" verbs. Such analyses may represent the root form of the verb {{lang|ja|書く}} as kak-, emphasizing the unchanging consonant k. "Unigrade" verbs are then referred to as "vowel-stem" verbs.{{cite book|chapter=Verbs|title=Handbook of Modern Japanese Grammar|last=Matsuoka McClain|first=Yoko|year=1981|publisher=The Hokuseido Press|pp=3–4}}

Here is a visualization that compares various verb conjugations to an extracted column of the gojūon table:

|-

! Volitional

| {{lang|ja|読もう}}
{{nihongo|||yomō}}

! {{nihongo krt||も|mo}}

|

|

|

|

|

!

|}

In the table above, the verb {{nihongo krt|to read|読む|yomu}} uses kana from all 5 rows of the gojūon table in its inflectional suffix—{{nihongo krt||ま|ma}}, {{nihongo krt||み|mi}}, {{nihongo krt||む|mu}}, {{nihongo krt||め|me}} and {{nihongo krt||も|mo}}—amongst its conjugations. Thus, it is classified as a "class-5" (or more formally "quinquegrade") verb. Meanwhile, the verbs {{nihongo krt|to see|見る}} and {{nihongo krt|to stop|止める|}} each use kana from only 1 row of the gojūon table in their verb-stem's suffix—{{nihongo krt||み|mi}} and {{nihongo krt||め|me}} respectively. Thus, they are classified as a "class-1" (or more formally "unigrade") verbs. {{Crossreference|(See also Japanese verb conjugations.)}}

All modern godan verbs are derived from historical yodan verbs.{{cite book|script-title=ja:日本語文法大辞典|last=Yamaguchi|first=Akiho|last2=Akiyama|first2=Hideaki|publisher=Meiji Shoin|date=15 March 2001|isbn=4-625-40300-6|script-chapter=ja:五段活用|p=261}} The distinction between these two classes relies solely on the interaction between the {{nihongo||未然形|mizenkei}} and the {{nihongo|"tentative"|推量|suiryō}} auxiliary {{nihongo||う|u}} (historically, {{nihongo||む|mu}}). Consider the verb {{nihongo||書く|kaku|"to write"}}:

• kaka- + -mu → kakamu (historical form) → kakau (historical form) → kakō (modern form)

The shift of vowels from au to ō was regular and expansive during Late Middle Japanese, and it practically introduced an additional {{nihongo||段|dan|in other words, vowel}} to the inflectional forms of yodan verbs:

The term {{nihongo||五段|godan}} is a fairly modern coinage. During the time when modern kana usage was being adopted to write {{nihongo|modern Japanese|口語|kōgo|{{lit|spoken language}}}} in place of historical kana usage, one of the changes concerned how such a form as kakō should be spelt. The modern spelling {{lang|ja|かこう}} was proposed along with godan as the name for the modernized yodan class. Traditionalist grammarians, on the other hand, would insist on such spelling as {{lang|ja|かかう}} to reflect the historical pronunciation kakau, and on the modern pronunciation being inferred from such spelling. Some argued that a single interaction with the auxiliary u did not justify creating an entire new grammatical class, given that the mizenkei does not involve a vowel shift with any other auxiliary:

• kaka- + -nai → kakanai
• kaka- + -nu → kakanu
• kaka- + -n{{efn|Alternative form of either "tentative" -mu or "negative" -nu.}} → kakan
• kaka- + -zu → kakazu

Moreover, the auxiliary -ta and the particle -te also notably alter the ren'yōkei:

• kaki + -ta/-te → kaita/te
• omoi + -ta/-te → omotta/te
• yomi + -ta/-te → yonda/de

Yet, such alterations are not reflected by either the term yodan or the term godan at all, despite occurring in both these supposedly different inflections (although in {{nihongo|classical Japanese|文語|bungo|{{lit|written language}}}}, these alterations in pronunciation must be inferred from the spellings). This means that exceptional interactions with auxiliaries and particles like these ought not to be the basis for naming verb classes.

Obviously, the spelling reform took place and the term godan became mainstream. Historical kana usage is now reserved only for the writing of classical Japanese, and yodan verbs are largely considered a classical Japanese class while godan verbs make up a fundamental part of modern Japanese.

Within Japanese language education, various terminologies are used in lieu of the Japanese nomenclature for "quinquegrade" and "unigrade" verbs.

In literature adopting the "Group I / II / III" terminology, the terms (I), (II) or (III) may be notated beside verbs.

Similarly, (う) or (る) may be notated beside verbs in literature adopting the "{{nihongo2|う-verbs}} / {{nihongo2|る-verbs}}" terminology.

{{seealso|Japanese verb conjugations}}

The terms "consonant stem verbs" and "vowel stem verbs" come from a pattern that emerges from studying the actual structure of the words rather than the written representation. When considering the invariant part of the verb (the verb stem), the final phoneme determines the classification of the verb group. If the verb stem's final phoneme:

• is a consonant, then it is a consonant stem verb (quinquegrade verb)
• is a vowel, then it is a vowel stem verb (unigrade verb)

There are criticisms of the consonant and vowel nomenclature:

1. When quinquegrade verbs end with {{nihongo krt||"う"|u}}, the verb's invariant stem always ends with a vowel, yet is still classified as having a consonant stem. For example, {{nihongo krt|to buy|買う|kau}} has the vowel "a" as the invariant suffix, yet it is still categorized as a "consonant stem verb".
   In these cases, this apparent expection is resolved by realizing that the verb's invariant stem ends in the consonant w. The w is normally suppressed, but surfaces in the negative form, as seen in {{nihongo krt|to not buy|買わない|kawanai}}. Traditionally these verbs ended in -hu, which is still seen on occasion in historical kana usage, and thus unambiguously ended in h.
   
   
2. When godan verbs end with {{nihongo krt||"つ"|tsu}}, the verb's invariant stem always ends with an "s" rather than a "t". Since the consonant stem terminology focuses on rōmaji, this could lead to conjugation errors. For example, {{nihongo krt|to wait|待つ|matsu}} in its negative conjugation does not become {{nihongo krt||"待つぁない"|matsanai}} as the consonant stem system might have one believe; the correct conjugation is {{nihongo krt|to not wait|待たない|matanai}}. The matter is resolved when phonemic notation of "tu" used by Kunrei-shiki romanization is applied instead.
   
   
3. In the case of the past-tense and te forms of conjugation, the 'invariant' stem changes such that the consonant is removed from all godan verbs (except verbs ending in {{nihongo krt||"つ"|tsu}} or {{nihongo krt||"す"|su}}). This means the defining characteristic of consonant stem verbs cannot be used to define consonant stem verbs for the past-tense or te forms. The true "invariant stem", which is consistent amongst all conjugations, precedes the so-called "invariant consonant".
   
   

Classifying verbs is simple in theory:

1. Take the verb in its plain, negative form. The result will be: verb-stem + {{nihongo krt||ない|nai}}
2. If the last character of the verb-stem (ignoring the "{{nihongo2|ない}}"):

::* rhymes with {{nihongo krt||〜ぁ|-a}}, then it is a quinquegrade verb

::* rhymes with {{nihongo krt||〜ぃ|-i}} or {{nihongo krt||〜ぇ|-e}}, then it is a unigrade verb

This classification system works for all Japanese verbs, with three exceptions: {{nihongo krt||ある|aru}} is a quinquegrade verb, and both {{nihongo krt||しない|shinai}} and {{nihongo krt||こない|konai}} are instead classified as irregular verbs.{{cite book |last1=Makino |first1=Seiichi |last2=Tsutsui |first2=Michio |title=A Dictionary of Basic Japanese Grammar |date=1989 |publisher=The Japan Times |location=Tokyo, Japan |isbn=978-47-89004-54-1 |edition=80 |page=578}}

In some Japanese dictionaries, the readings of conjugable words may have the stem and the inflectional suffix separated by a dot (・). For example, the adjective {{nihongo krt|red|赤い|akai}} may be written as {{nihongo krt||あか・い|aka·i}} to separate the static prefix from the dynamic suffix.

This system also describes the verb group classification: in quinquegrade verbs, the dot is placed before the last kana; in unigrade verbs, the dot is placed before the last 2 kana (except for 2-kana unigrade verbs, which have no dot).

However, regardless of the dot's position, the inflectional suffix is always the last kana of any unigrade verb.

A caveat of accurately classifying verb groups is that you must have pre-existing knowledge of the verb's negative form. In practice, people tend to learn the verb's plain form first. As such, Japanese language educators usually teach strategies for naive verb classification. Whilst such strategies are not comprehensive, they generally remain useful in the context of regular daily conversations that language beginners will likely encounter. Here is one such strategy:

Naive strategies, such as this one, tend to misidentify quinquegrade verbs ending with {{nihongo krt||る|ru}}—specifically, when quinquegrade verbs rhyme with {{nihongo krt||〜ぃる|-iru}} or {{nihongo krt||〜ぇる|-eru}}. Therefore, when a unigrade verb is concluded from a naive strategy, it is more efficient to confirm the verb's classification in a dictionary. However, there are other rules-of-thumb to more accurately discriminate such verbs.

If a dictionary is unavailable, it becomes difficult to discriminate quinquegrade verbs from unigrade verbs when they rhyme with {{nihongo krt||〜ぃる|-iru}} or {{nihongo krt||〜ぇる|-eru}}. The following heuristics aim to improve the accuracy of naive classification:

• There are far more quinquegrade verbs than unigrade verbs.
• Verbs that do not rhyme with {{nihongo krt||〜ぃる|-iru}} or {{nihongo krt||〜ぇる|-eru}} are quinquegrade verbs.

:This includes verbs that rhyme with {{nihongo krt||〜ぁる|-aru}}, {{nihongo krt||〜ぅる|-uru}} and {{nihongo krt||〜ぉる|-oru}}, which are quinquegrade verbs.

• The majority of verbs that rhyme with {{nihongo krt||〜ぃる|-iru}} are quinquegrade verbs.

:248 of the 419 {{nihongo krt||〜ぃる|-iru}} verbs [ca. 60%] listed in JMdict are quinquegrade verbs.{{Citation needed|date=March 2021|reason=This data appears out-of-date, please link to a filtered search result of the JMdictDB}}

• The majority of verbs that rhyme with {{nihongo krt||〜ぇる|-eru}} are unigrade verbs.

:2886 of the 3013 {{nihongo krt||〜ぇる|-eru}} verbs [ca. 95%] listed in JMdict are unigrade verbs.{{Citation needed|date=March 2021|reason=This data appears out-of-date, please link to a filtered search result of the JMdictDB}}

Kana and kanji based heuristics for {{nihongo krt||〜ぃる|-iru}} and {{nihongo krt||〜ぇる|-eru}} verbs:

• Verbs written entirely in hiragana are quinquegrade verbs. For example, {{Nihongo krt|to be surprised|びびる|bibiru}} and {{Nihongo krt|to fall forward|のめる|nomeru}} are quinquegrade verbs.
• Kanji verbs with 1 okurigana and 3+ syllables are quinquegrade verbs. For example, {{Nihongo krt|to pledge|契る|chi-gi-ru}} and {{Nihongo krt|to ridicule|嘲る|a-za-ke-ru}} are quinquegrade verbs.
• Kanji verbs with 2 okurigana are usually unigrade verbs. For example, {{Nihongo krt|to get up|起きる|okiru}} and {{Nihongo krt|to eat|食べる|taberu}} are unigrade verbs.
• Kanji verbs with 2 syllables are inconclusive. For example, {{Nihongo krt||切る|ki-ru}} and {{Nihongo krt||見る|mi-ru}} are both 2-syllable verbs, yet belong to different categories (quinquegrade and unigrade, respectively)

There are many quinquegrade verbs which may be mistaken for being unigrade verbs in some cases {{See above|{{section link||Naive verb classification}}, above}}. On the surface, this may seem like a problem that only affects conjugation patterns, since quinquegrade verbs and unigrade verbs conjugate differently {{Crossreference|(See main article: Japanese verb conjugations)}}. However there are many verbs that, despite having the same spelling, have different meanings and belong to different verb groups. For example:

When reading verbs such as these, the correct word meaning can be ascertained through the different kanji or accentuation. {{Crossreference|(See also Japanese pitch accent.)}} However, ambiguity is usually removed if the verbs have been conjugated somehow, because different word groups conjugate with slightly varying pronunciations. For example:

Since there are so many quinquegrade verbs that resemble unigrade verbs, it is impractical to create or memorize an exhaustive list of words.

• Japanese verb conjugation
• Honorific speech in Japanese
• Japanese adjectives
• Japanese particles
• Japanese grammar
• 五段活用

{{notelist}}

{{reflist}}

• {{cite book|chapter=Late Middle Japanese grammar|first=Hirofumi|last=Aoki|editor-first=Bjarke|editor-last=Frellesvig|editor-first2=Satoshi|editor-last2=Kinsui|title=Handbook of Historical Japanese Linguistics|series=Handbooks of Japanese Language and Linguistics|publisher=De Gruyter|year=2024|isbn=978-1-61451-401-5}}
• {{Cite book

| surname = Frellesvig | given = Bjarke

| title = A History of the Japanese Language

| publisher = Cambridge University Press | location = Cambridge | year = 2010

| isbn = 978-0-521-65320-6

}}

• {{cite book|year=2001|chapter=Prose and Poetry of Heian Japanese|last=Iwasaki|first=Shoichi|title=Textual Parameters in Older Languages|editor-first3=Lene|editor-last3=Schøsler|editor-first2=Pieter|editor-last2=van Reenen|editor-first=Susan C.|editor-last=Herring|isbn=90-272-3702-6|publisher=John Benjamins Publishing Company|series=Current Issues in Linguistic Theory}}
• {{cite book|chapter=Development of Accusative Case Marker|first=Shigeru|last=Miyagawa|title=Structure and Case Marking in Japanese|date=2 December 2019|isbn=0-12-613522-3|publisher=Academic Press|series=Syntax and Semantics}}
• {{cite book|title=Irregular Phonological Marking of Japanese Compounds|last=Vance|first=Timothy J.|year=2022|publisher=De Gruyter|series=The Mouton NINJAL Library of Linguistics|isbn=978-3-11-075501-5}}
• {{cite book|year=1887|location=Yokohama|publisher=Kelly & Walsh, Limited|title=A Synopsis of All the Conjugations of the Japanese Verbs|authorlink=Guido Verbeck|first=Guido Herman Fridolin|last=Verbeck}}
• {{cite book|year=2020|title=A Descriptive and Comparative Grammar of Western Old Japanese|last=Vovin|first=Alexander Vladimirovich|authorlink=Alexander Vovin|series=Languages of Asia Series|publisher=Brill|isbn=978-90-04-42211-7|edition=2nd}}

• [https://www.sljfaq.org/afaq/which-godan.html Archive of the Usenet newsgroup sci.lang.japan forums], a non-exhaustive list of ~iru and ~eru quinquegrade verbs
• [https://web.archive.org/web/20101228022950/http://respectthebeard.com/japanese/ Aeron Buchanan's Japanese Verb Chart], a concise summary of all Japanese verbs conjugations on one sheet of A4

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Godan and ichidan verbs

Category:Japonic verbs

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