If you know only the first (PPI, dictionary) form, the verb is a consonant stem unless it ends in '-eru' or '-iru'. If it does end in one of those, you can't tell what the stem is, but it's more likely to be a vowel stem than a consonant stem.
Form | Formation | Irregular | Regular | ||||||
---|---|---|---|---|---|---|---|---|---|
Vowel Stem | Consonant Stem | W Stem | |||||||
です to be (copula) |
来る to come |
する to do |
行く to go |
ある there is |
食べる to eat |
書く to write |
買う to buy |
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Stem | This isn't a verb form, and can't even be written in Japanese, but can be useful to learn instead of the ます and て forms so that you can tell apart the vowel, consonant and W stems. | (none) | ki-/ku-/ko- | shi-/su- | ik- | ar- | tabe- | kak- | ka(w)- |
Present Positive Informal | Also called the "dictionary form", because it's how you'll find the verb listed in the dictionary. Except for です. They're also shown above in the headings, spelled in kanji. | だ I am |
くる I come |
する I do |
いく I go |
ある there is |
たべる I eat |
かく I write |
かう I buy |
Present Negative Informal | For vowel stems, drop the '-ru' of the positive and add '-nai'. For consonant stems, drop the '-u' of the positive and add '-anai'. For W stems, drop the '-u' of the positive and add '-wanai'. | ではない、 じゃない I am not |
こない I do not come |
しない I do not do |
いかない I do not go |
ない There is not |
たべない I do not eat |
かかない I do not write |
かわない I do not buy |
Past Positive Informal | Take the て form and change the '-e' to '-a'. | だった I was |
きた I came |
した I did |
いった I went |
あった There was |
たべた I ate |
かいた I wrote |
かった I bought |
Past Negative Informal | Take the Present Negative Informal and change the '-i' to '-katta'. | ではなかった、 じゃなかった I was not |
こなかった I did not come |
しなかった I did not do |
いかなかった I did not go |
なかった There was not |
たべなかった I did not eat |
かかなかった I did not write |
かわなかった I did not buy |
て form | For a vowel stem, drop the '-ru' and add 'te'. For a consonant stem, change '-ku' to '-ite', '-gu' to '-ide', '-su' to '-s(h)ite', '-t(s)u' to '-tte', '-nu' to '-nde', '-bu' to '-nde', '-mu' to '-nde', '-ru' to '-tte'. For a W stem, change '-u' to '-tte'. It's regular, but complicated enough that it's worth memorising the form when you learn the verb. | で being |
きて coming |
して doing |
いって going |
あって there being |
たべて eating |
かいて writing |
かって buying |
Present Positive Formal | Also called the ます form. If you know this form and the Present Positive Informal, you can figure out what all the rest are. | です I am |
きます I come |
します I do |
いきます I go |
あります there is |
たべます I eat |
かきます I write |
かちます I buy |
Present Negative Formal | Take the Present Positive Formal, drop the '-u' and add '-en'. | ではありません、 じゃありません I am not |
きません I do not come |
しません I do not do |
いきません I do not go |
ありません There is not |
たべません I do not eat |
かきません I do not write |
かいません I do not buy |
Past Positive Formal | Take the Present Positive Formal, drop the '-su' and add '-s(h)ita'. | でした I was |
きました I came |
しました I did |
いきました I went |
ありました There was |
たべました I ate |
かきました I wrote |
かいました I bought |
Past Negative Formal | Take the Present Negative Formal and add '-deshita'. | ではありませんでした、 じゃありませんでした I was not |
きませんでした I did not come |
しませんでした I did not do |
いきませんでした I did not go |
ありませんでした There was not |
たべませんでした I did not eat |
かきませんでした I did not write |
かいませんでした I did not buy |
Passive Present Positive Informal | Begin with the (active) Present Positive Informal. For a vowel stem, drop the '-ru' and add '-rareru'. For a consonant stem, drop the '-u' and add '-areru'. For a W stem, drop the '-u' and add '-wareru'. The form you get is always a vowel stem, and can be inflected just like the active form to get the negative, past and formal. | (none) | こられる (no passive meaning in English) |
される I am done |
いかれる (no passive meaning in English) |
(none) | たべられる I am eaten |
かかれる I am written |
かわれる I am bought |
Passive Present Negative Informal | こられない (no passive meaning in English) |
されない I am not done |
いかれない (no passive meaning in English) |
たべられない I am not eaten |
かかれない I am not written |
かわれない I am not bought |
|||
Passive Past Positive Informal | こられた (no passive meaning in English) |
された I was done |
いかれた (no passive meaning in English) |
たべられた I was eaten |
かかれた I was written |
かわれた I was bought |