List of Official and Japanese Conjugation Names?


TL;DR: Do you know of a good recourse for official and Japanese names of the Japanese conjugations?

I have realized that I have learnt many forms that I dont know precisely, such as realis, irrealis, conclusive and so on. For example, Genki teaches verbs as る- and う-verbs, but “officially” they are called ichidan (一段) and godan (五段). The “must” conjugation 行かなければ いけない is “negative hypothetical” + potential. When I first learnt this, I did not learn the constructions, or the names There are still many forms I read and use that I am not aware of. I would like detailed information about the grammar constructions and the official and Japanese names. Is there any good website or recourse for a overview of this? I find something by googling here and there, but I have not found a very clear and complete explanation. For example, Bunpro has a lot of good explanation (at least after the recent updates), but it is still not complete.

Thank you


When you mention 一段 and 五段 it sounds like you want the grammar the way Japanese linguists would break it down. They would break down 行かなければ as 行か (未然形 irrealis form of 行く) + なけれ (仮定形 hyopthetical form of ない) + ば (接助 conjunctive particle) and いけない, which you mentioned as potential, I think, but there’s an argument that いける has become its own verb distinct from the potential form of 行く it originally came from and that this is just the irrealis plus ない of that. Though I suppose there’s some room to disagree there.

Is it just completeness or curiosity that you want to know these? Many, many people function just fine without knowing them. If you are curious then that’s a valid reason.

Your best options for finding these linguistics terms in Japanese would be in descriptions of Japanese grammar written in Japanese.


Most things you were taught as a single conjugation are actually a conjugation and attaching an auxiliary verb/adjective (called 助動詞). This Japanese-only grammar website has a lot of the information you want. The 用言 section contains the main parts of speech, and any subsection with 活用 in the title lists the six types of conjugations for that part of speech. Then the 助動詞 section contains the auxiliary verbs/adjectives that you attach after a specific conjugation. If you’re familiar enough with textbook grammar and have some practical language experience you should be able to piece it together.


A bit of a shameless plug, but I’m launching a Japanese grammar series on Twitter that touches on some of these ideas without the technical terms, so if you find that you’re having trouble with the way things are explained in Japanese and you want something to compare them with, then you might want to take a look. (I’m avoiding the technical terms on purpose so that people who haven’t studied grammar before can get an idea of what’s going on.)


But technical terms are exactly what @TobyOne is looking for


Yes, which is why I said that perhaps just the concepts involved might be helpful. I personally found that the explanations one could find in English were not that intuitive, and the technical terms probably don’t help unless you’ve already studied some formal grammar for another language, though some fairly detailed explanations exist, like this one on Wikipedia:

However, I can provide something of a starting point with the technical terms here:
You’ve got
仮定形=hypothetical (modern Japanese) / 已然形=realis (classical Japanese)

Dictionaries always list them in this order. How can you remember that order? One way is to take AIUEO as the ‘alphabetical order in Japanese’ and to check the final vowel for each form/stem for godan verbs:
未然形 – A
連用形 – I
終止形 – U
連体形 – U
仮定形 / 已然形 – E
命令形 – E

So you get AIUUEE.

The 未然形 is used for negation, and that makes sense because it expresses things that haven’t happened yet (hence ‘irrealis’=not real/realised). It’s also what you attach helper verbs to for the causative and the passive. The 連用形 very literally links to 用言 (‘declinable words’ aka words whose form changes) like adjectives, verbs and adverbs, and can be used to replace the て-form. (In fact, the て-form is actually just 連用形+て historically.) The 終止形 is the one used to end sentences, and the 連体形 comes before nouns to modify them. In modern Japanese, these two are usually identical, so it seems weird that there are two terms, but in Classical Japanese, the two were consistently different. The 仮定形 is the thing we put before ば in modern Japanese, and looks like part of the potential form for godan verbs. In Classical Japanese, if the condition in a conditional statement was not fulfilled and was purely hypothetical, you would use 未然形+ば instead, and if you meant ‘because’ or ‘when’ or something else regarding a condition that was already fulfilled, you would use 已然形+ば, because it’s something already realised (realis). However, as we can see, now, the two usages have more or less merged into the modern 仮定形+ば. Finally, the 命令形 is the one used for given orders, like「いけ!」, and it’s still around today. Another usage of it is in phrases like いずれにせよ, which is roughly ‘whichever one chooses’ i.e. ‘anyway, no matter what, etc.’ In this case, it’s sometimes called the 放任形.

I hope that’s a decent summary. I don’t think I know much more than that, aside from a few random conjugations of old helper verbs and the fact that stuff like the 意志形 (the ‘volitional’, which usually ends in -ou) is the result of a sound change involving む, then う and the あ of the 未然形, which is something I hope to cover at some point in my series (or perhaps just as a random tidbit on Twitter).

PS: The same forms look kind of different for adjectives, and the things they attach to are a little different as well, but I don’t think I’ll go into those right away, and you’ll probably come across them after you’ve taken a look at verbs.


Thank you. It is both for completeness and curiosity I wonder. The type of analysis you gave is the exact type of thing I am curious about. The resource looks nice, but probably a bit too advanced for me. Thanks!

Hi, thank you. Good luck on your twitter series! As mentioned, it might not be what I am looking for, but I will have a look. Multiple explanations from different perspectives are always nice. And thanks for the explanation, I will try to puzzle things together in my head.


Thanks! I hope you find all the information you need to understand and satisfy your curiosity. :slight_smile:

EDIT: I figured I should just add that because I’m trying to avoid technical terms, some of the names I give to stems won’t line up with traditional Japanese terms perfectly. For example, I will discuss a ‘negative’ stem for い-adjectives, but the truth is that (as I will mention) it’s the same as the 連用形 for い-adjectives, which I call the ‘adverbial’ form. On the other hand, the ‘negative stem’ I’ve already mentioned for verbs really is the 未然形.

The reason for these discrepancies is that I’m trying to help people learn the stems in the context of practical usage, and I’ll only bring in more complete theory later. The real 未然形 for い-adjectives is 〜かろ, and I think this will make sense once one knows that the volitional form (意志形, which is a more ‘modern’ grammar term) for godan verbs is actually the result of 未然形+う causing the final -AU to morph into -OU, which is why the volitional stem ends in -O.

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