The Japanese language has two types of regular verbs that involve the stem, and can be referred to as Japanese consonant and vowel verbs.
The two groups of verbs are:
- consonant-stem, godan-katsuyō (五段活用, "5-class conjugation"), Group I, or -u verbs; and
- vowel-stem, ichidan-katsuyō (一段活用, "1-class conjugation"), Group II, or -ru verbs.
Most verbs are consonant-stem, but vowel-stem verbs are also common, hence the numbering "Group I" (consonant-stem, more common) and "Group II" (vowel-stem, less common). Sometimes categorization is expanded to include "Group III" (special cases) for the irregular verbs する suru and 来る kuru; note however that there are other Japanese irregular verbs, though they are generally only slightly irregular.
Consonant-stem verbs end in -u (-au, -iu, -uu, -ou), -ku, -gu, -su, -tsu, -nu, -bu, -mu or -ru, but not -eu, -zu, -dzu, -fu, -pu, or the defective columns -yu or -wu.
All vowel-stem verbs end in either -iru or -eru. However, not all verbs ending in -iru or -eru are vowel-stem verbs; for example, hashiru, "run", is a consonant-stem verb. Verbs ending in -aru, -uru and -oru also exist, and are all consonant-stem.
The Japanese names ("5-class" and "1-class") are based on the number of vowel suffixes used to form verb roots for conjugations. Classical Japanese had more verb groups (such as 2-class and 4-class) which are archaic in Modern Japanese.
Consonant-stem verbs conjugate differently from the vowel-stem verbs. Consonant-stem verbs conjugate after a consonant, and vowel-stem verbs conjugate after a vowel, as can be seen in the following examples:
|Plain form||yom.u ("read")
読む (godan, u-verb)
走る (godan, u-verb, -iru verb)
見る (kami ichidan, ru-verb, -iru verb)
食べる (shimo ichidan, ru-verb, -eru verb)
- Note that colloquially the ら ra is dropped meaning these two become 見れる mireru and 食べれる tabereru.
- Can also be written as mi.eru. The difference is like the difference between "can see" and "can be seen." Two consonant-stems that have also irregular potential forms are ik.eru/ik.areru ("can go") and kik.eru/kik.oeru ("can hear"). Other irregular potential forms are suru→dekiru ("can do") and kuru→korareru ("can come").
Consonant-stem verbs ending in -u (-au, -iu and -ou) may not appear to conjugate "after a consonant"; for example, the polite form of kau (買う, "buy") is kaimasu (ka.u → ka.imasu). However, the stem is in these cases technically considered to end in the consonant w. The w is normally suppressed, but surfaces in the negative form, as in kaw.anai ("does not buy"). Traditionally these verbs ended in -hu, which is still seen on occasion in historical kana usage, and thus unambiguously ended in h.
The terms "consonant-stem" and "vowel-stem" come from considering the invariant part of the verb (the verb stem) on the basis of phonemes – concretely, by writing in rōmaji. This is an abstract perspective, as the consonant stem itself never occurs independently, but only with a following vowel, as Japanese words are formed of morae – concretely, writing in kana. For example, while the stem of yomu is yom-, the bare *yom is not an independent word.
The standard Japanese terms, ichidan and godan, literally "one row" and "five rows", more formally monograde and pentagrade, correspond to the number of different morae (kana) that appear in the stem forms of the verb, which are then optionally combined with a suffix to form a conjugated word. Formally, verbs are classified by which column of the gojūon their stem ends in, with vowel stem verbs further distinguished into i and e type. For example, 読む yomu is of マ行五段活用 ma-gyō go-dan katsuyō "ma-column five-row conjugation" type, as its stem form end in each of the five rows of the ま column, namely まみむめも:
- 読ま よま yoma- as in yomanai (negative, irrealis),
- 読み よみ yomi- as in yomimasu (polite non-past),
- 読む よむ yomu- as in yomu (plain non-past; dictionary form),
- 読め よめ yome- as in yomeba (conditional),
- 読も よも yomo- as in yomō (yomou) (hortative/volitional).
Note that the volitional o stem is historically the negative a stem with euphonic sound change – and the o stem is only used for the volitional form – so these verbs were traditionally called 四段 yodan "four-row, tetragrade", omitting the o form.
While the above uses are the most common uses of the respective stems, they are used in various other ways, particularly the i stem – for example 読み物 yomi-mono "reading material"; compare 食べ物 tabe-mono "food" for vowel stem.
By contrast, vowel stem verbs have a single stem form, ending either in i or e, accordingly as -iru or -eru. These are referred to respectively as 上一段 kami ichi-dan "upper one-row" and 下一段 shimo ichi-dan "lower one-row", due to i being above e in the aiueo vowel ordering. In full terminology, the column of the final kana is also listed. For 見る みる miru is of マ行上一段活用 ma-gyō kami ichidan katsuyō "ma-column upper one-row conjugation" type and has stem:
- 見 み mi-
while 食べる たべる taberu is of バ行下一段活用 ba-gyō shimo ichidan katsuyō "ba-column lower one-row conjugation" and has stem:
- 食べ たべ tabe-
In Japanese dictionaries, in the readings of conjugable words the stem and the inflectional suffix are separated by a dot (・), as in 赤い あか・い aka.i "red". This is used to distinguish verb type, with consonant stem verbs having only the last kana treated as suffix, while in vowel stem verbs the last two kana are treated as suffix. The column 行 of the conjugation form corresponds to the kana immediately after the dot. For example:
- 帰る かえ・る kae.ru "return" – consonant stem ラ行五段
- 変える か・える ka.eru "change" – vowel stem ア行下一段
Note that for one-row verbs with only two kana, the entire verb is treated as a suffix, and no dot is displayed, as it would appear before the word. For example:
- 要る い・る i.ru "need" – consonant stem ラ行五段
- 居る いる iru "be (animate)" – vowel stem ア行上一段
The terms "Group I", "Group II", and "Group III" are primarily used in Japanese language education, and may be notated as (I), (II), (III) next to a verb. Similarly, the terms "u verb" (��� verb) and "ru verb" (る verb) are educational terms, and may be notated as （う） or （る）.
Verbs ending in -iru and -eru
Vowel-stem verbs, such as 見る miru "to see" and 食べる taberu "to eat," end either in -iru or -eru (there are no other basic-form endings for this group), but some consonant-stem verbs have these endings, too (e.g. 散る chiru "to scatter," 抓める tsumeru "to pinch"), and there are also "homophone verbs" that have either a vowel stem or a consonant stem (e.g. ikiru vowel 生きる "to live, to stay alive," consonant 熱る "to become sultry"; shimeru vowel 閉める "to close [something]," consonant 湿る "to be damp").
Rules of thumb
- There are more consonant verbs than vowel verbs.
- All verbs not ending in -iru/-eru are consonant-stem verbs; this includes -aru/-uru/-oru verbs and verbs with a vowel ending in the basic form, such as 買う kau "to buy" and 言う iu "to say."
- Over half of verbs ending in -iru have a consonant stem (e.g., of the 419 -iru verbs listed in EDICT, 248 [ca. 60%] have a consonant stem), and the majority of verbs ending in -eru has a vowel stem (e.g., of the 3013 -eru verbs listed in EDICT, 2886 [ca. 95%] have a vowel stem).
- If the vowel i/e of the ending -iru/-eru is part of a kanji (as in 契る chigi-ru "to pledge" and 嘲る azake-ru "to ridicule"), as opposed to being part of an okurigana, chances are high that the verb has a consonant stem.
- However, this rule is not applicable for two-syllable verbs (⾒る mi-ru, for example, has a vowel stem) and verbs written only in hiragana (for example, びびる bibiru "to be surprised" and のめる nomeru "to fall forward" have consonant stems). Some consonant-stem verbs also have the syllable with the ending vowel written in hiragana, e.g. 混じる ma-jiru "to mingle" and the mentioned-above verb 抓める tsu-meru "to pinch."
- -eru verbs having the e sound written in hiragana listed in EDICT: 2934 (ca. 97% of -eru verbs listed there, of them 2901 vowel verbs and 33 consonant verbs)
- -eru verbs having the e sound in a kanji listed in EDICT: 139 (of them 39 vowel verbs and 100 consonant verbs).
Examples of conjugation
The "homophone verbs" iru (vowel: いる (居る) to be [animated] ; consonant: 炒る to boil down, to roast, 入る to go in, 要る to need) and eru (vowel: 得る to get, to obtain; consonant: 彫る to carve, 選る to choose, 啁る to ridicule):
|Vowel stem (-iru)||Consonant stem (-iru)||Vowel stem (-eru)||Consonant stem (-eru)|
|Potential form 1||i.rareru||ir.eru||e.rareru||er.eru|
1 Potential forms of consonant verbs are conjugated like vowel verbs: ireru / ereru → iremasu / eremasu, etc. The same is true for passive forms (irareru / erareru → iraremasu / eraremasu, etc.). In vowel verbs, potential and passive forms are identical (irareru / erareru).
Rule of thumb: In vowel verbs, the basic-ending -ru is completely replaced by the new ending (e.g. iru / eru → inai / enai), while in consonant verbs, the -r sound is kept and followed by another vowel, to which the new ending is added (e.g. iru / eru → iranai / eranai). However, in the -te/-ta forms, consonant verbs drop the -r sound and replace it by -tte/-tta (e.g. itte, itta / ette, etta), while vowel verbs have -te/-ta (e.g. ite, ita / ete, eta).
Lists of verbs (examples)
The following lists are not complete; feel free to add other verbs.
Homophone vowel-stem and consonant-stem verbs ending in -iru
|Verb||Vowel stem||Consonant stem|
|chibiru||禿びる to get blunt, to dull, to wear out||ちびる 1. to wet oneself, to shit oneself 2. to be miserly|
|hiru||干る to dry 嚏る to sneeze||放る to expel (from the body)|
|ikiru||生きる to live, to stay alive||熱る to become sultry|
|iru||射る to shoot 居る to be (animated)
鋳る・鑄る to cast, to mint, to coin 癒る to calm down
|煎る・炒る・熬る to boil down, to roast 入��� to go in 要る to need
沒る・没る to set beyond the Western horizon (i.e. the sun)
|kiru||着る・著る to put on clothing||霧る to become misty 斬る to kill someone with a blade 切る to cut 剪る to cut, to prune, to trim (plants) 截る to cut (e.g. cloth) 伐る to cut down (e.g. trees) 鑽る・鑚る to start a fire (with wood-wood friction or by striking metal against stone)|
|komiiru||込み居る to push in, to be crowded||込み入る・込入る to push in, to be crowded, to be complicated|
Homophone vowel-stem and consonant-stem verbs ending in -eru
|Verb||Vowel stem||Consonant stem|
|eru||得る・獲る to get, obtain||彫る・雕る・鐫る to carve|
選る・択る to choose
|fukeru||更ける・深ける to get late, to advance, to wear on
蒸ける to become ready to eat (as a result of steaming)
1. to indulge in, to give oneself up to, to be obsessed by 2. to be engrossed in, to be lost in, to be absorbed in
|furikaeru||振り替える・振りかえる・振替える to change (e.g. a bill), to transfer (e.g. money), to switch over, to move over||振り返る・振りかえる・ふり返る・振返る to turn head, to look over one's shoulder, to turn around, to look back|
1. to bend down, to bow down
|臥せる to lie down, to retire, to go to bed|
|heru||経る・歴る to pass (time/through)||減る to decrease|
|hineru||陳ねる to age||捻る・拈る・撚る|
1. to twist, to wrench, to turn (off/on), to wring (a neck)
|kaeru||変える to change, to alter
換える・替���る・代える to exchange
|帰る・還る・歸る to return|
返る・反る to return 孵る to hatch out
|kakeru||掛ける・懸ける1. to hang (e.g. picture), to hoist (e.g. sail), to raise (e.g. flag) 2. to sit 3. to be partway (verb), to begin (but not complete) 4. to take (time, money), to expend (money, time, etc.) 5. to make (a call)
6. to multiply 7. to secure (e.g. lock) 8. to put on (glasses, etc.) 9. to cover 10. to burden someone
11. to apply (insurance) 12. to turn on (an engine, etc.), to set (a dial, an alarm clock, etc.) 13. to put an effect (spell, anaesthetic, etc.) on 14. to hold an emotion for (pity, hope, etc.) 15. to bind
16. to pour (or sprinkle, spray, etc.) onto 17. to argue (in court), to deliberate (in a meeting), to present (e.g. idea to a conference, etc.) 18. to increase further 19. to catch (in a trap, etc.) 20. to set atop
21. to erect (a makeshift building) 22. to hold (a play, festival, etc.) 23. (after -masu stem of verb) indicates (verb) is being directed to (someone)
駆ける・駈ける 1. to run (race, esp. horse), to dash 2. to gallop (one's horse), to canter 3. to advance (against one's enemy) 4. to soar, to fly 5. to run, to dash
|翔る・駆ける・翔ける 1. to soar, to fly 2. to run, to dash|
|mochikaeru||持ち替える・持替える・持ち換える to change way one holds something (esp. transferring it from one hand to the other)||持ち帰る・持帰る to bring back, to carry home, to take out (e.g. food)|
|mikaeru||見変える・見替える to forsake one thing for another||見返る to look back|
|nameru||舐める・嘗める,甞める 1. to lick 2. to taste 3. to experience (esp. a hardship) 4. to make fun of, to trer with contempt||滑る to be slippery, to be slimy|
|neru||寝る・寐る to sleep||練る・煉るto temper, to refine, to knead|
|okikaeru||置き換える・置き替える to replace, to move, to change the position of||起き返る to rise, to erect, to get up|
|shimeru||閉める to close (something)||湿る to be damp|
|suberu||統べる・総べる to control, to supervise||滑る・辷る 1. to glide, to slide 2. to fail 3. to drop, to go/come down, to fall (e.g. in status)|
|takeru||炊ける to be boiled/cooked/ready
長ける・闌ける 1. to excel at, to be proficient 2. to grow old 3. to ripen 4. to rise high (e.g. the sun)
|猛る 1. to rage, to be fierce 2. to be excited|
���る to roar, to howl
Consonant-stem verbs ending in -iru
Note: Homophone verbs listed above are not repeated here.
|Verb||Kanji and/or hiragana||English|
|aburagiru||脂ぎる||to be greasy|
|bibiru||びびる||to be surprised|
|dojiru||どじる||to mess up (coll.)|
|hojiru||穿る||to pick, dig out|
|hotobashiru||迸る||to gush, spurt|
|ibiru||いびる||to torment, roast|
|ijiru||弄る||to fiddle with|
|kishiru||きしる||to become misty|
|kishiru||軋る||to squeak, creak|
|kojiru||抉る||to gouge, wrench|
|kubiru||括る||to grip, strangle|
|kujiru||抉る||to gouge, scoop|
|mairu||参る||to come/go - humble|
|meiru||滅入る||to feel depressed|
|mikubiru||見縊る||to belittle; to despise|
|mojiru||捩る||to parody, to twist|
|mushiru||毟る||to pluck, to pick, to tear|
|nijiru||躙る||to edge forward|
|nonoshiru||罵る||to abuse verbally|
|ochiiru||陥る||to fall, sink|
|omoiiru||思い入る||to ponder, to contemplate|
|omoikiru||思い切る||to dare to (usually in the form omoikitte (思い切って) or omoikitta (思い切った).)|
|sebiru||せびる||to pester for|
|tagiru||滾る||to boil, to seethe|
|tamagiru||魂消る||to be frightened|
|tochiru||とちる||to muff lines|
|yajiru||弥次る・野次る||to jeer at|
|yogiru||過る||to pass by, to drop in|
|yojiru||捩る||to twist, distort|
Consonant-stem verbs ending in -eru
Note: Homophone verbs listed above are not repeated here.
|Verb||Kanji and/or hiragana||English|
|aseru||焦る||to be in a hurry|
|haberu||侍る||to attend on|
|hirugaeru||翻る||to turn over, to wave|
|hoteru||火照る||to flush, to feel hot|
|kageru||陰る||to become dark, to be in shadow or shade|
|kuneru||くねる||to be crooked|
|kutsugaeru||���る||to be overturned|
|numeru||滑る||to be slippery|
|seseru||挵る||to pick, play with|
|shaberu||喋る||to talk, to chat|
|shigeru||茂る||to grow thick|
|shikeru||湿気る||to become damp|
|soberu||そべる||to lie sprawled|
|yomigaeru||蘇る||to be brought back to life, to be refreshed|
- Seiichi Makino and Michio Tsutsui, A dictionary of intermediate Japanese grammar, published by The Japan Times, ISBN 4-7890-0775-8.
- sci.lang.japan FAQ's list of iru and eru consonant-stem verbs.
- Aeron Buchanan's Japanese Verb Chart, a concise summary of all Japanese verbs conjugations on one sheet of A4