As a studies of Japanese I've come across two distinct ways to group verbs for purposes of remembering how to conjugate them.

う動詞 / る動詞
Group1 / Group 2

Pacerier mentioned a verb1 and verb5, can someone explain to me how the verbs are divided for this system?

Also, how do Japanese people learn the different conjugations patterns? What system for verb classification do they use?

this question may boarder on off-topic, but i think as a Japanese learner, I'd like to be able to ask verb related questions to a Japanese person, but if i say う動詞, unless they are familiar with non-foreigners learning Japanese, they don't know what I'm talking about.

  • verb1 is the same as Group 2. and verb5 is the same as Group 1
    – Pacerier
    Commented Jun 21, 2011 at 5:32

3 Answers 3


The two types are:

[五段動詞]{ご・だん・どう・し} ー means "5-level verbs". This is the group where the conjugations match the 5 vowel sounds of their respective kana ending. A common 五段動詞 is 書く. It conjugates along the k- column of the hiragana table:

ない  書ます  書  書ば/書る  書

We can see that its conjugations hit all 5 of the k-kana:   か き く け こ

Note that 五段動詞 that end in 〜う (like 会う) have a conjugation of  い う え お  (会ない for the negative). This is not arbitrary, and there are historical reasons for this, but I will not attempt to get into them here.

The other type are the [一段動詞]{いち・だん・どう・し} (your るverbs). However, these can be broken down based on (I believe) the last character of their "base form" (the part before the る). The kana columns go -a -i -u -e -o, where the -u is considered the "center". They are classified as "upper" ([上]{かみ}) or "lower" ([下]{しも}) based on the center.

  • 着る is 上一段 since き is one level "above" the center (which would be く)
  • 食べる is 下一段 since べ is one level "under" the center (which would be ぶ)

There are such things as 上二段 and 下二段 verbs, but I don't think they exist in modern spoken Japanese. At least that's what 広辞苑 implies.

  • 二段 verbs had been converted into 一段 verbs over time. Commented Jun 20, 2011 at 1:57
  • You are right about 上二段 and 下二段. They existed in Classical Japanese, and they became 上一段 and 下一段 in Modern Japanese. Commented Jun 20, 2011 at 1:57
  • Is it intentional that you mixed the Arabic numeral 5 with the kanji numeral 一? I have never seen 五段活用 written with the Arabic numeral, but I am not sure if it is usual or not because my experience with the materials on the Japanese grammar is quite limited. Commented Jun 20, 2011 at 15:06
  • I don't think so. Editing.
    – istrasci
    Commented Jun 20, 2011 at 15:09
  • 2
    here are also some guides on the net speaking about 四段 verbs instead of 五段 verbs, but they are also just a group of verbs in Classical Japanese that got converted to 五段 verbs in the modern language. Basically, modern Japanese has only 五段, 一段 and irregular (くる + する) verbs and nothing more, but there is one group of 五段 verbs that behave slightly differently: the 警護 verbs ending in -aru such as いらっしゃる, おっしゃる and ござる. EDICT/JMDICT classifies them as "(v5aru)".
    – Boaz Yaniv
    Commented Jun 21, 2011 at 9:19

The two main classifications of regular verbs are 一段 and 五段, named after the number of forms their base takes.

  • 食べる -> 食べ
  • 入る -> 入ら・入り・入る・入れ・入ろ

Within 一段 there are two further classifications, although both are conjugated the same way.

  • 上一段: 見る, 落ちる, etc.
  • 下一段: 寝る, 当てる. etc.
  • what's the difference between the upper ichi-dan and lower ichi-dan? are Ru-verbs the same as ichi-dan? and what about special verbs like Kuru? are they go-dan? Commented Jun 20, 2011 at 1:54
  • 3
    The difference between 上一段 and 下一段 is whether they end with -iru or -eru. 「来る」 and 「する」 are irregular verbs and do not fit into either regular verb type. Commented Jun 20, 2011 at 1:59
  • I'm wondering, which form of 入る begins with 入ろ?
    – Tomalak
    Commented Apr 18, 2017 at 17:46
  • @Tomalak: Volitional form: 「入ろう」. Commented Apr 18, 2017 at 17:51

There is a pretty good and complete overview of the two groups (一段/五段, which can also be seen as "U-dropping" and "RU-dropping" in romaji) on this page.

する and くる have separate, exception-filled, conjugations of their own (sometimes referred to as サ行変格活用/カ行変格活用).

Note that, like many technical grammatical question, I really don't think you will get a very useful answer from a non-specialist native. Japanese verb conjugation rules are fairly straightforward (though filled with exceptions) and most Japanese simply "know" which is which, without necessarily knowing why. Quite the same way your average English speaker would be at a loss explaining which verbs are regular and which aren't, and how irregular verbs work.

  • 3
    I might even add by experience that just asking about things like "活用" (conjugation) or "一段/五段" may be answered by a gaze and something like "sorry, I have no idea what you're talking about." P!
    – Axioplase
    Commented Jun 20, 2011 at 2:52

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