In classical Japanese, many uses of 形容詞{けいようし} had あり "embedded" in them, e.g.:

  • 熱からず = 「熱し」の連用形+「あり」の未然形{みぜんけい}+「ず」
  • 熱かりたり = 「熱し」の連用形+「あり」の連用形{れんようけい}+「たり」
  • 熱かれ = 「熱し」の連用形+「あり」の命令形{めいれいけい}
  • 熱かる人 = 「熱し」の連用形+「あり」の連体形{れんたいけい}

while others did not:

  • 熱くす = 「熱し」の連用形+「す」
  • 熱し = 「熱し」の終止形{しゅうしけい}
  • 熱き人 = 「熱し」の連体形{れんたいけい}

It seems that there is a plain form and an あり form for most of the conjugations:

       plain    あり
未然形  -ku      -kara
連用形  -ku      -kari
終止形  -si      missing
連体形  -ki      -karu
已然形  -kere    -kare
命令形  missing  -kare

My question is why certain usages of 形容詞 used the あり version and others didn't. Did the あり have some sort of semantic meaning?

(The original motivation for this was the question of why the past tense of 形容詞 is かった rather than くた or った or いた, while the て-form is くて.)

(P.S., the majority of my experience with classical Japanese is reading about its grammar, not actually reading old poems or stories. I suspect if I had more actual experience I'd be able to understand why あり is required in these places.)

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    I think that 熱からず, 熱かりたり, 熱かる, 熱かれども, and 熱かれ are contractions of 熱くあらず, not 熱きあらず, and so on. Commented Feb 5, 2013 at 4:22
  • @TsuyoshiIto Yes, you're right, but I wasn't sure if I should mark 熱く as 「熱き」の連用形 or not, because it seems like 熱かり is the 連用形 for most (all?) purposes. I'm not sure how I should note this in my deconstructions. Commented Feb 5, 2013 at 4:27
  • I've modified it to say 「熱き」の連用形 since that certainly makes more sense than just having nothing there. Commented Feb 5, 2013 at 4:44
  • Ah, now I see that you are using 熱き as the word itself without specifying its form. Dictionary form 熱し is more common when one does not want to specify its form, but this is just a notational convention. Commented Feb 5, 2013 at 4:52
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    熱く is definitely one of the 連用形 forms of 熱し. One of the usages of 連用形 is as a modifier of a verb, and the example 熱くす shows that 熱く can modify verb す. Commented Feb 5, 2013 at 4:55

2 Answers 2


I have come to the following conclusion:

The あり form of 形容詞 arose to support 助動詞. The non-あり form is only used with 名詞 (via the 連体形), 動詞・形容詞 (via the 連用形), and 接続助詞.

To make sure that this explanation is not circular, 助動詞 and 接続助詞 need to be differentiated using some other property — thankfully, 接続助詞 cannot be predicative while 助動詞 can.

Some examples...


  • 未然形:熱からず、熱からむ
  • 連用形:熱かりき、熱かりけり、熱かりたり
  • 連体形:熱かるべし


  • 連用形:熱くなり、熱くす


  • 未然形:熱くば
  • 連用形:熱くて
  • 已然形:熱ければ、熱けれど、熱けれども

(In the case of 接続助詞「て」, it's true that it comes from 助動詞「つ」, but it seems that it was reanalyzed as a 接続助詞, allowing for the wider distribution: ○熱くて、x熱くつ.)

I think the reasoning goes like this: 助動詞 need to attach to a verb (whether this is a purely syntactic constraint, or some sort of semantic one, I don't know), so あり was inserted to help out. 接続助詞 on the other hand have no such constraint.

And then, once the あり form arose, some things that could already be done gained a new form, such as 熱からば and 熱かる人 — I do not think their meaning was different from the non-あり form.

  • Hmm. This seems like a good answer! It does explain why, despite having a non-あり 未然形 of 〜く, we can't say 「暑くず」 in proper CJ. But we can say 暑くない in Modern Japanese! Is it because the predicate forms merged with the non-predicate forms in general, as a part of the huge 連体形/終止形 merge?
    – ithisa
    Commented Jan 2, 2014 at 3:47
  • Hmm. 暑くない could be analyzed as 暑く + modern negative of ある, so it is still an 〜あり form?
    – ithisa
    Commented Jan 2, 2014 at 3:48
  • I suppose む in 悲しけむ should be a 助動詞.
    – Yang Muye
    Commented Mar 24, 2014 at 19:00

The same function as it does in modern Japanese: to supplement the missing conjugations. Japanese adjectives have a limited conjugation: 連用形 -ku, 終止形 -si, and 連体形 -ki. So how would you make a negative adjective without a 未然形? Or how would you make a conjection without 已然形 (modern 仮定形)? Easy: since it can already modify a verb (連用形 -ku), just add a the most basic verb ar-. As a verb, it can easily supplement the missing conjugations.

  • Thanks, this helps some. It does not make the 連用形 case so clear though. Why would the past tense be 熱かりたり rather than 熱くたり? (Are both forms valid in all contexts? I think I've only seen the former. But even so, why would there be a need for two?) --- Also, this suggests that ある is semantically vacuous and is only there for conjugations. I think this makes sense to me, since having a copula there would not really mesh with what I know about 形容詞 at least. Commented Feb 5, 2013 at 5:29
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    @DariusJahandarie Note that -tar- is a contraction of -te + ar-. This -te (actually the 連用形 of -tu) can and does attach to the 連用形 of adjectives: atuKUTE, o(p/f)oKUTE etc.
    – Dono
    Commented Feb 5, 2013 at 6:20
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    I am afraid that an important point is missing here. In classical Japanese, adjectives have both plain conjugation and -kar- conjugation. In case of ku-adjectives, plain conjugation: 未然形 -ku, 連用形 -ku, 終止形 -si, 連体形 -ki, 已然形 -kere, and 命令形 is missing; -kar- conjugation: 未然形 -kara, 連用形 -kari, 終止形 is missing, 連体形 -karu, 已然形 -kare, 命令形 -kare. Many slots have both a plain form and a -kar- form. If the -kar- forms were invented to supplement the missing conjugations, in which sense were these conjugations missing? Why do adjectives have two forms in the same slot? (more) Commented Feb 5, 2013 at 19:14
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    (cont’d) The answer is because the two forms play different roles, but the real question is what those “different roles” are. Hence the question “What function did あり perform in classical Japanese 形容詞?” Commented Feb 5, 2013 at 19:15

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