～ようだ (Formal): Resemblance and Evidence-Based Inference in Japanese

～ようだ is the formal, written-leaning Japanese auxiliary for three related meanings: direct resemblance (X is like Y), figurative simile with まるで, and evidence-based inference (it seems X).¹²³⁴ For learners moving from N4 to N3, it is the form to use in essays, reports, and polite speech where the casual sibling みたい would feel out of place.⁵⁶⁷

Overview

What ～ようだ means

～ようだ puts three readings on one stem. Native 口語文法 (colloquial grammar) references group them as 比況 (likening A to B), 推定 (inference grounded in evidence), and 例示 (exemplification: picking one instance as a representative of a category).⁸⁹⁴

Each reading has a diagnostic adverb that you can insert before ようだ to confirm the sense: どうやら or どうも tests inference, まるで or あたかも tests simile, and たとえば tests exemplification.⁸⁴

Across all three senses, ようだ inflects on the な-adjective (形容動詞) paradigm. In other words, it follows the same form pattern as みたい and as 形容動詞 generally.⁸¹⁰¹¹⁷

ようだ behaves like a な-adjective

ようだ is not a fixed sentence-ender. It conjugates: attributive ような (modifies a noun), adverbial ように (modifies a verb or adjective), polite ようです, plain past ようだった. Treat it as a な-adjective whose stem happens to be よう.¹⁰¹¹

Register and JLPT placement

ようだ is the formal, written-leaning member of the inferential-suffix family. It occupies the same evidence cell as みたい. The main contrast between the two is register, not evidence type.¹²²⁵⁶

Wasabi puts it bluntly: ようだ is preferred in writing, みたいだ is preferred in speech.⁵ Bunpro adds that ようだ is "more formal than みたい; less common in casual conversation."⁷

The polite ようです and the academic ようである are stylistic upshifts on the same paradigm, not separate grammar points; both are covered below under "Polite ようです and written ようである."

J-Compass places this article at N3. Bunpro lists plain ようだ at N4 because it appears in N4 textbooks like Genki II,⁷ but the depth covered here (three readings, register split, formation contrast with みたい, まるで pairing, 婉曲 softening) matures at N3.^13141516

The three readings at a glance

Reading	Diagnostic adverb	Prototype
Direct resemblance (比況)	まるで, あたかも	彼の部屋はゴミ箱のようだ。 ("His room is like a trash can.")
Simile with まるで (比喩)	まるで required, あたかも optional	まるで夢のようだ。 ("It is just like a dream.")
Evidence-based inference (推定)	どうやら, どうも	どうやら風邪を引いたようだ。 ("Apparently I've caught a cold.")

Sources for the table rows: resemblance ⁸⁴¹⁷; simile ¹⁸⁶¹⁴; inference ⁸⁴¹⁹.

The fourth native-grammar sense, 例示 (exemplification: 彼のような立派な政治家 "a respectable politician like him"), folds into the resemblance reading because the formation is identical (noun + の + ような + N) and learner-level treatments do not separate it.⁸⁴

Formation and attachment rules

ようだ attaches to the 連体形 (attributive form) of whatever precedes it.⁹ In modern Japanese, this gives a simple four-way attachment frame: verbs and い-adjectives attach in their plain form, な-adjectives need な, and nouns need の.

Verb + ようだ

Plain (普通形) verbs attach directly to ようだ in any tense: non-past, past, negative, or ている.⁴¹⁸⁷¹⁵ 大辞泉's structural rule is that ようだ attaches to the 連体形 of 用言 (inflecting words), and the 連体形 of a verb in modern Japanese is identical to its plain form.⁹

今日きょうは寒さむくなるようだ。²⁰
"It looks like it's going to get cold today."

嵐あらしはやんだようだ。²⁰
"It appears the storm has passed."

彼かれはここに来こないようだ。⁷
"It seems he won't come here."

今日きょうは落おち込こんでいるようですね。²⁰
"You seem down today."

い-adjective + ようだ

Plain い-adjectives attach directly to ようだ in any tense.⁴¹⁸⁷ Because the 終止形 (sentence-final form) and 連体形 (attributive form) of an い-adjective are identical, no connector is needed.⁹

このスープは辛からいようだ。¹³
"This soup seems spicy."

彼女かのじょはうれしくないようだ。²⁰
"She doesn't seem happy."

な-adjective + な + ようだ

The な-adjective stem takes な before ようだ in the non-past affirmative. Past and negative forms attach in the plain form (元気だった, 元気じゃない).^41871521 The な is required because ようだ attaches to the 連体形 of a 形容動詞, and the 連体形 of a な-adjective is the -な form.⁹¹¹

田中たなかさんは元気げんきなようだ。⁷
"Mr. Tanaka seems to be doing well."

あの人ひとは有名ゆうめいなようだ。¹³
"That person appears to be famous."

私わたしは無知むちだったようだ。²⁰
"It seems I was a bit ignorant."

Noun + の + ようだ

A noun takes の before ようだ in the non-past affirmative. Past and negative use the plain copula forms (子供だった, 子供じゃない).^4185721 大辞泉 captures the rule structurally: ようだ attaches to 体言 (nominals) only with the 格助詞 の inserted ("体言、…に格助詞『の』の付いた形").⁹

The の is mandatory and is what diverges from みたい

The most common attachment error at this level is writing 子供ようだ by analogy with the casual 子供みたい. ようだ requires の before any noun; みたい takes the bare noun. The contrast sits exactly at this morpheme.⁵²²²³

雨あめのようだ。²⁰
"It looks like rain."

ここは会議室かいぎしつのようだ。¹³
"This looks like a meeting room."

今日きょうの天気てんきは台風たいふうのようだ。⁷
"Today's weather is like a typhoon."

Conjugating ようだ itself

ようだ inflects on the 形容動詞型 paradigm. The full Wiktionary table is: 未然形 ようだろ ／ 連用形 ようだっ・ように・ようで ／ 終止形 ようだ ／ 連体形 ような ／ 仮定形 ようなら ／ 命令形 ―.¹¹ 大辞泉 records the same paradigm,⁹¹⁰ and 精選版日本国語大辞典 sums it up: 「形容動詞に等しい」.¹⁰

The headline forms a learner needs:⁷²⁴²⁰

Form	Function	Example
ようだ	sentence-final (plain)	寒いようだ
ような	attributive, modifies a noun	夢のような時間
ように	adverbial, modifies a verb or adjective	子供のように笑う
ようです	polite-style sentence-final	今日は授業がないようです
ようだった	past plain	大人になったようだった
ようである	written / academic sentence-final	(see "Polite ようです and written ようである" below)

The role split between ような and ように is fixed: ような precedes a noun (連体), while ように precedes a verb, adjective, or adverb (連用).⁷²⁴ The 命令形 slot is empty for ようだ, as it is for 形容動詞 generally.¹¹

Reading 1: Direct resemblance ("X is like Y")

Sentence-final ようだ for resemblance

The 比況 use states a resemblance at the sentence end. The structure is <thing A> は <thing B> + のようだ for noun comparators, and the plain-form attachments above for predicate comparators.⁸⁴¹⁷

This is distinct from 推定 inference. In resemblance, the speaker is asserting a likeness (B as a metaphorical predicate for A), not guessing whether A is the case.³⁴ You can test the 比況 reading by inserting まるで or あたかも before the comparator; the sentence stays grammatical and the resemblance reading is reinforced.⁸⁴

それは本当ほんとうに夢ゆめのようだ。²⁰
"That's truly like a dream."

彼女かのじょは死しんだように眠ねむっていた。⁶
"She was sleeping as if dead."

うちの夫おっとは一人ひとりで何なにもできないし、まるで赤あかちゃんのようだ。¹⁸
"My husband can't do anything on his own; he is just like a baby."

Attributive ような modifying a noun

ような is the 連体形 of ようだ. It modifies a following noun and builds a noun phrase in which the head noun resembles the comparator.¹¹⁷²⁴

With a noun, the shape is noun + の + ような + <head noun> (子供のような笑顔 "a smile like a child's").¹⁷²⁴ With a predicate, use the plain form + ような (食べすぎたような顔 "a face like one that has overeaten").²⁴

あなたのような人ひとは嫌きらいです。⁶
"I dislike people like you."

トムさんとのデートはまるで夢ゆめのような時間じかんだった。¹⁸
"My date with Tom was like time out of a dream."

驚おどろくような景色けしきを見みた。²⁴
"I saw scenery that was startling."

Adverbial ように modifying a verb or adjective

ように is the 連用形 of ようだ. It modifies a following verb, adjective, or adverb, expressing "in the manner of" or "like."¹¹⁷²⁴

With a noun, the shape is noun + の + ように + <verb / adjective> (子供のように笑う "laugh like a child").¹⁷¹⁸

ように-resemblance and ように-purpose look identical on the surface

ように-resemblance ("in the manner of") and ように-purpose ("so that") share the same shape because both are built on the 連用形 of ようだ. They are separate grammar points. Disambiguate by what precedes ように: noun + の + ように is resemblance; a plain potential or negative verb + ように is usually purpose.²⁴

ジェームスさんはまるで日本人にほんじんのように日本語にほんごを話はなす。¹⁸
"James speaks Japanese just like a Japanese person."

彼かれは魚さかなのように泳およぐのが上手じょうずだ。¹⁸
"He swims skillfully, like a fish."

娘むすめは天使てんしのように可愛かわいい。¹⁸
"My daughter is as cute as an angel."

Reading 2: Simile with まるで ("just like…")

The まるで…ようだ pairing

まるで is the standard adverb for figurative simile. It strengthens a non-literal resemblance and pairs idiomatically with ようだ and the casual みたい.¹⁷¹⁸¹⁴

The pairing rule is まるで + (V plain ／ イA ／ ナA + な ／ N + の) + ようだ ／ ような ／ ように.¹⁸¹⁴ まるで can be omitted; the resemblance reading survives because ようだ still anchors the simile. The pairing is one-directional: まるで does not co-occur with らしい or with hearsay そうだ.¹⁴

In this pairing, the speaker signals figurative, not literal, intent. That is what gives まるで…ようだ its almost-but-not-quite tone.¹⁹

まるで夢ゆめのようだ。⁶
"It is just like a dream."

彼女かのじょが描かいた犬いぬの絵えは本当ほんとうに素晴すばらしい。まるで生いきているようだ。¹⁸
"Her painting of the dog is truly wonderful; it is just like it's alive."

先生せんせいはちょっと間違まちがえただけで怒おこるし、まるで鬼おにのようだ。¹⁸
"Sensei gets angry at the slightest mistake; it's just like an ogre."

Bridge to かのように / かのような

The N2 counterfactual extension is built as embedded か + の + ようだ: ～かのようだ states that something seems or feels like X even though it is not actually X.²¹

It is built on the same auxiliary ようだ, and its inflectional shapes follow ようだ exactly: かのように (連用), かのような (連体), かのようだ (終止), polite かのようです.⁹¹¹ The simile-anchor adverbs まるで and あたかも commonly pair with かのように, one register step up from まるで…ようだ.

この銅像どうぞうは精巧せいこうに作つくられていて、まるで生いきているかのようだ。²¹
"This statue is so finely made that it is just as if it were alive."

Reading 3: Evidence-based inference ("it seems / it appears")

What "evidence-based" means for ようだ

推定 ようだ expresses a conclusion the speaker has drawn from observed or felt evidence: a wet street supports 雨が降ったようだ, tired posture supports 疲れているようだ, and an empty house supports 留守のようだ.³⁸⁴

大辞泉's gloss captures the evidentiality (how the speaker knows): 「一定の根拠をもった不確かな断定を表す」 ("expresses an uncertain judgment based on definite evidence").¹¹ Asano-Cavanagh's NSM explication foregrounds the same thing: the speaker has thought about the situation and reached a conclusion, with more commitment than rashii and a less impressionistic basis than sooda.²

You can test this reading by inserting どうやら or どうも before ようだ: 「（どうやら）留守のようだ」 stays natural and the inference reading is reinforced.⁸⁴

The full four-way comparison with そう, らしい, and みたい lives in the modal-suffixes hub; for this article, the contrasts that matter most are:

The diagram organizes the contrasts that the surrounding paragraphs cite individually.²³⁵

Sample inferences across sentence types

Here is one inference example for each attachment type, to anchor the formation rules in the 推定 reading.

風邪かぜを引ひいたようだ。⁴
"It seems I've caught a cold."

教室きょうしつに来きたけど誰だれもいない。今日きょうは授業じゅぎょうがないようだ。²⁰
"I went to the classroom but no one was there. It seems there's no class today."

田中たなかさんは元気げんきなようだ。⁷
"Mr. Tanaka seems to be doing well."

あの人ひとは警察けいさつのようだ。⁵
"That person appears to be a police officer."

Softening function in formal writing and speech

The 婉曲 (softening) use of ようだ takes a claim the speaker could assert flatly and downgrades it to "the way it seems." This avoids sounding categorical and helps protect the listener's face.¹⁹¹³

日本語教師の広場 frames the motivation as cultural: 「そのものずばりを、直接的に述べることは品格にかける、という考え方が根底にあります。そこで、多少、あいまいさを残した表現が好まれます」 ("the underlying view is that stating things flatly lacks refinement; expressions that leave a little ambiguity are preferred").¹⁹ The same source: 「相手に失礼にならないようにと、配慮をした婉曲表現としても使われ」 ("ようだ is also used as a softening expression out of consideration not to be rude to the listener").¹⁹

日本語ジャーナル aligns the use to formal speech and writing: 「はっきりと断定することを避けて控えめに言う」 ("avoids making definitive assertions and expresses things modestly"), in cases of 「相手の気持ちに配慮したり、言いにくいことを言う場合」 ("when one is being considerate of the other's feelings, or saying something hard to say").¹³

In business and polite contexts, ようです often softens facts the speaker is certain of. A host saying 「全員そろったようですので、ミーティングを始めたいと思います」 knows everyone is present but softens the assertion with ようです.¹⁹

Use ようです to soften, even when you are sure

The 婉曲 use is the reason a fluent host softens "everyone is here" to 全員そろったようです. The hedge is a politeness move, not an admission of uncertainty. Hard assertions register as blunt; ようです registers as considered.¹⁹¹³

ちょっと、地味じみなようですね。¹⁹
"It looks a bit plain, doesn't it?"

ちょっと塩味しおあじが足たりないようですね。¹⁹
"It seems a bit under-salted, doesn't it?"

全員ぜんいんそろったようですので、ミーティングを始はじめたいと思おもいます。¹⁹
"It looks like everyone has arrived, so I'd like to begin the meeting."

Nuance, register, and contrast

ようだ vs みたい: when to pick which

ようだ and みたい share readings (resemblance and inference) and a な-adjective inflection pattern (ような／ように vs みたいな／みたいに). They differ in register: ようだ is formal and written, while みたい is casual and spoken.²⁵⁶⁷²⁵

The main formation contrast is at the noun: ようだ requires の (子供のような), while みたい takes the bare noun (子供みたいな).⁵²²²³ Wasabi's minimal pair: 「あの人は警察のような(だ／です)」 (formal) vs 「あの人は警察みたい(だ／です)」 (casual).⁵ Use みたい in conversation; use ようだ in essays, reports, and news writing.⁵²⁵

あの人ひとは警察けいさつのようだ。⁵
"That person looks like a police officer." (formal)

あの人ひとは警察けいさつみたいだ。⁵
"That person looks like a cop." (casual)

ようだ vs そうだ-appearance

そうだ-appearance is based on a single immediate sensory clue, and it is restricted to adjective stems and verb stems: い-adjectives drop い (おいしい → おいしそう), な-adjectives drop な (元気な → 元気そう), and verbs take the ます-stem (降る → 降りそう).³⁵

ようだ is based on accumulated or circumstantial evidence and attaches to plain forms (with な for な-adjectives and の for nouns).⁴⁵⁷

A form test makes the contrast concrete: 「おいしそう」 (stem + そう, "looks delicious right now") vs 「おいしいようだ」 (plain + ようだ, "from what I can tell, it appears to be delicious").⁵

ようだ vs らしい

らしい packages information the speaker got from outside (heard, read, observed by others) and keeps the speaker at arm's length from the claim. ようだ presents the speaker's own conclusion from their own evidence and commits more.²³⁵

Asano-Cavanagh's NSM explications render rashii as more arm's-length ("I think I can say something like this about X") and yooda as more committed ("I think it is like this"). This captures the commitment gap precisely.²

The rain test makes the contrast portable: 雨が降ったらしい reads as "apparently it rained" (someone told me), while 雨が降ったようだ reads as "it seems it rained" (I see wet streets).³⁵

The four-way map

ようだ sits alongside そう (appearance), そうだ (hearsay), らしい, and みたい on a four-axis map of indirect evidentials. The side-by-side decision tool with full formation rules and evidence-type contrasts is in the modal-suffixes overview; this article stays focused on ようだ.²³⁵

The take-away from the comparison: ようだ is the formal end of the seeing-and-reasoning group. It occupies the same evidence cell as みたい, but with the register lever in the opposite direction.⁵⁷

Polite ようです and written ようである

ようです is the polite-style form. It functions wherever ようだ does, in polite speech and in formal writing.⁷²⁰ JLPT Sensei's polite example: 「今日は落ち込んでいるようですね」 ("You seem down today").²⁰

ようである is the literary and academic form, built by replacing the plain copula だ with である. It is the same な-adjective pattern swap that turns 静かだ into 静かである.⁹¹⁰¹¹ ようである appears in academic prose and editorials where である-style is the baseline. It carries no semantic difference from ようだ, only a register upshift.

大辞泉's conjugation paradigm lists 連用形 ようで. This is the morphological hook that licenses ようである (である is the 連用形 of だ followed by ある).⁹¹¹

Good to know

Forgetting の before the noun

The most common attachment error at N3 is dropping the の before a noun. A learner coming from the casual みたい may reflexively write 子供ようだ; the correct form is 子供のようだ.⁵²²²³ 大辞泉 captures the rule structurally: ようだ attaches to a 体言 only via the 格助詞 の.⁹

子供こどものようだ。⁵
"He is like a child."

Confusing ように-resemblance with ように-purpose

Resemblance ように (子供のように笑う "laugh like a child")¹⁸²⁴ looks identical on the surface to purpose ように (分かるように説明する "explain so that one understands"). Both are built on the 連用形 of ようだ, but they are different grammar points.

The disambiguation rule is what precedes ように: a noun + の + ように is resemblance; a plain potential or negative verb + ように is usually purpose.²⁴

子供こどものように笑わらう。¹⁸
"Laugh like a child."

ようだ is auxiliary, not slang: 様 + だ

大辞泉 records the etymology: 「形式名詞『よう（様）』に断定の助動詞『だ』の付いたもので、中世末期以降の語」 ("formed by attaching the assertive auxiliary だ to the formal noun よう（様）; a word from the late-medieval period onward").⁹

ようだ is a classical 助動詞 (auxiliary) still spelled with the kanji 様 in formal and literary registers (子供の様だ). The casual みたい, by contrast, is a Meiji-period colloquial contraction of 見たような.¹¹ The register split between the two is etymological, not arbitrary.

Use ようです in business and polite contexts; ようである in academic prose

ようです softens claims for face-saving in polite speech (「全員そろったようですので…」)¹⁹ and is the default in formal-but-not-academic writing.

ようである, built by swapping だ for である on the same な-adjective paradigm, belongs to the academic and editorial register.⁹¹⁰¹¹ There is no semantic shift, only a register upshift.

Evidence type, not certainty, distinguishes the inferential suffixes

A compact mnemonic for the four-way family: ようだ is my evidence, my conclusion; らしい is their evidence, my report; hearsay そうだ is their words, my relay; appearance そう is one visual clue right now.²³⁵

Certainty roughly tracks evidence quality, but the primary axis is the source of the evidence. ようだ commits because the speaker owns the inference.²

See also

• Inferential Suffixes in Japanese: ～そう, ～よう, ～らしい, ～みたい Compared
• ～みたい (Casual): "Like" and "Seems Like" in Japanese
• ～かのように / ～かのような: How to Say "As If" in Japanese (the Counterfactual Resemblance)
• ～でしょう / ～だろう: Conjecture and Confirmation in Japanese
• ～はず: How to Express Logical Expectation in Japanese
• ～ように: How to Say "So That" / "In Order To" in Japanese

References

Footnotes

1. Makino, Seiichi and Michio Tsutsui. A Dictionary of Basic Japanese Grammar. The Japan Times, 1986. Entry for yoo da (the formal counterpart of mitai da; treats yoo da as the auxiliary expressing resemblance and evidence-based conjecture). ↩

2. Asano-Cavanagh, Yuko. "Semantic analysis of evidential markers in Japanese: Rashii, yooda and sooda." Functions of Language, vol. 17, no. 2, 2010, pp. 153–180. John Benjamins. https://doi.org/10.1075/fol.17.2.01asa (Romanization in this source: rashii, yooda, sooda; Natural Semantic Metalanguage explication.) ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰

3. Teramura, Hideo (寺村秀夫). Nihongo no shintakusu to imi (日本語のシンタクスと意味), Volume 2. Tokyo: くろしお出版 (Kurosio), 1984. Standard reference treating 様態・推量・伝聞 modality of そうだ・ようだ・らしい. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

4. 国際交流基金（Japan Foundation）「日本語教育通信 文法を楽しく：よう（１）」. https://www.jpf.go.jp/j/project/japanese/teach/tsushin/grammar/201307.html. Japan-Foundation teacher-training resource; identifies the 推量, 比喩・比況, and 例示 senses with illustrative sentences (「風邪を引いたようだ」「家が天国のように見える」「母が言ったように、早く帰ればよかった」), and lists the 動詞普通形 ／ イ形容詞普通形 ／ ナ形容詞＋な ／ 名詞＋の attachment frame. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷

5. Wasabi (Wasabi-jpn). 「How to Express Judgments: そうだ, ようだ, みたいだ, and らしい」. https://wasabi-jpn.com/magazine/japanese-grammar/how-to-express-judgments/. Quoted: 「ようだ is a formal word and preferred in writing, while みたいだ is a casual word and preferred in speech」; minimal-pair noun attachment 「あの人は警察のような(だ／です)」 vs 「あの人は警察みたい(だ／です)」. (limitation) Tier-4 publisher; used for the register and minimal-pair claims that align with primary references above. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹ ↩²² ↩²³

6. Wasabi (Wasabi-jpn). 「How to use ～ようだ in Japanese」. https://wasabi-jpn.com/magazine/how-to-speak-japanese/how-to-use-youda-in-japanese/. Two-reading framing (conjecture and simile); ようだ as appropriate for formal writing and everyday conversation, with みたいだ「a lot more casual」; example bank including まるで夢のようだ / 死んだように眠っていた. (limitation) Tier-4 publisher. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷

7. Bunpro. 「ようだ (JLPT N4)」. https://bunpro.jp/grammar_points/ようだ. Formation table for 動詞 ／ い形容詞 ／ な形容詞＋な ／ 名詞＋の; conjugation as a な-adjective into ような (attributive) and ように (adverbial); register note 「more formal than みたい; less common in casual conversation」. (limitation) Tier-5 learner platform; cited for the JLPT-N4 placement and the consolidated attachment table, corroborated against tier-1 references for content. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰

8. 国立国語研究所. 「国語の文法（口語文法）：助動詞『ようだ』をマスターしよう」. https://www.kokugobunpou.com/助動詞/ようだ/ (口語文法 reference; identifies the three senses 推定・比況（たとえ）・例示, the disambiguating-adverb test, and the 形容動詞型 conjugation paradigm.) (limitation) Independent 口語文法 (school-grammar) reference rather than a NINJAL publication; corroborated against 大辞泉 and Wiktionary below. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰

9. 『デジタル大辞泉』(小学館), entry 様だ（ようだ）, via kotobank. https://kotobank.jp/word/様だ-653191. Quoted attachment rule: 「用言、助動詞『れる』『られる』『せる』『させる』『ない』『たい』『らしい』『ます』の連体形、体言、一部の副詞に格助詞『の』の付いた形、コソアド系の連体詞に付く」; quoted etymology: 「形式名詞『よう（様）』に断定の助動詞『だ』の付いたもので、中世末期以降の語」. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³

10. 『精選版日本国語大辞典』, entry 様だ（ようだ）, via kotobank. https://kotobank.jp/word/様だ-653191. Quoted: the conjugation is 「形容動詞に等しい」. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

11. Wiktionary contributors. 「ようだ」. ウィクショナリー日本語版. https://ja.wiktionary.org/wiki/ようだ. Full conjugation table (未然形 ようだろ ／ 連用形 ようだっ・ように・ようで ／ 終止形 ようだ ／ 連体形 ような ／ 仮定形 ようなら ／ 命令形 ―); etymology 様だ (yō-da), from 様 (yō, "appearance / manner"). ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³

12. Makino, Seiichi and Michio Tsutsui. A Dictionary of Intermediate Japanese Grammar. The Japan Times, 1995. Related-expressions notes under mitai da and rashii position yoo da on the formal / written end of the same evidence space as mitai da. ↩

13. 日本語ジャーナル「婉曲を表す『ようだ』の例文・文法解説【JLPT N3 grammar】」. https://japanese-language-education.com/for-overseas-learners/youda-enkyoku/. Quoted: 「はっきりと断定することを避けて控えめに言う」; 「相手の気持ちに配慮したり、言いにくいことを言う場合」; pins the 婉曲 use at N3. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷

14. Bunpro. 「まるで…ようだ (JLPT N3)」. https://bunpro.jp/grammar_points/まるで-ようだ. Pins the まるで…ようだ pairing at N3; pairing pattern (まるで＋V／イA／ナA＋な／N＋の＋ようだ); notes まるで pairs with みたい as an alternative but does not list らしい / そうだ as compatible. ↩ ↩² ↩³ ↩⁴ ↩⁵

15. hedgehog-japanese 「ようだ／ようです（推量）【文法-N3/N4 Grammar】」. https://hedgehog-japanese.com/grammar/jlpt-n3/you-3/. Places 推量 ようだ at the N3/N4 boundary; same 普通形 attachment frame with the two connector traps (ナ形 だ→な, 名詞 だ→の). (limitation) Pedagogy blog; cited for the level-boundary placement. ↩ ↩² ↩³

16. nihongo-career「JLPT N3 Grammar List – Explanations, Examples & Practice Test」. https://nihongo-career.com/tips/2025/10/18/quickly-master-jlpt-n3-grammar-list-practice-test/. Pedagogical placement of ようだ in the N3 grammar list under "Probability & Appearance," with the three senses (inference / resemblance / 婉曲) called out. (limitation) Pedagogy aggregator; corroborates the N3 reach. ↩

17. 日本語教師の広場「比況の表現『～ようです』」. https://www.tomojuku.com/blog/youda/hiyu/. Quoted: 「比況とは、ほかのものに例えていう言い方です」; 「副詞『まるで』を、よく一緒に使います」; attachment frames for 言いきり形, 連体修飾形, 連用修飾形 (動詞 ／ い形容詞) all built on 名詞＋の＋ようだ／ような／ように. ↩ ↩² ↩³ ↩⁴ ↩⁵

18. 日本語NET「【JLPT N3】文法・例文：まるで〜ようだ（比喩）」. https://nihongokyoshi-net.com/2020/01/08/jlptn3-grammar-youda/. Pins まるで…ようだ at N3; gives the four-way attachment frame (N＋の／イA／ナA＋な／V plain) and the まるで-omissibility note. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷

19. 日本語教師の広場「『推量』の婉曲表現『～ようです』」. https://www.tomojuku.com/blog/youda/enkyoku/. Quoted: 「はっきりと断定できないとき」「断定できると思ったときでも、相手の感情を傷つけないように」; 「そのものずばりを、直接的に述べることは品格にかける、という考え方が根底にあります。そこで、多少、あいまいさを残した表現が好まれます」; 「相手に失礼にならないようにと、配慮をした婉曲表現としても使われ」. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹

20. JLPT Sensei. 「N4 Grammar: ようだ (you da)」. https://jlptsensei.com/learn-japanese-grammar/ようだ-you-da-meaning/. JLPT placement, formation table, conjugation table (ようだ / ような / ように / ようです / ようだった), and numbered example sentences (verbatim 雨のようだ / 今日は寒くなるようだ / 嵐はやんだようだ / 私は無知だったようだ / ほか). (limitation) Pedagogy aggregator; used as the audit trail for example sentences. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹

21. 毎日のんびり日本語教師「【Ｎ４文法】～ようだ／ように／ような」. https://mainichi-nonbiri.com/grammar/n4-youda/. Full attachment frame (動詞 plain / い形容詞 plain / な形容詞＋な or である / 名詞＋の); the four senses framing (比喩・例示・推測・引用); quoted example 「この銅像は精巧に作られていて、まるで生きているかのようだ」 and others. ↩ ↩² ↩³ ↩⁴

22. LTL Japanese.「Expressing Similarity in Japanese: With よう, みたい & っぽい」. https://ltl-japanese.com/grammar-bank/similarity/. Noun + みたい attaches directly (no の), noun + のようだ requires の; ようだ "very commonly used in conversations" but more formal than みたい. (limitation) Commercial language-school blog; used to corroborate the noun-attachment minimal pair already cited from Wasabi. ↩ ↩² ↩³

23. jpyokoso. 「みたいな vs. ような：Which is Usually Used By Japanese?」. https://jpyokoso.com/mitaina-vs-youna/. Corroborates noun + のような (formal) vs noun + みたいな (casual) and the literary / written register tilt of ようだ in business / academic text. (limitation) Language-learning blog. ↩ ↩² ↩³

24. Bunpro. 「ように・ような (JLPT N4)」. https://bunpro.jp/grammar_points/138. Confirms the role split: ように modifies verbs / adjectives (adverbial), ような modifies nouns (attributive); same N4 placement. (limitation) Tier-5 learner platform. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰

25. Maggie Sensei.「How to use みたい ( = mitai)」. https://maggiesensei.com/2015/11/11/how-to-use-みたい-mitai/. Supports the casual / colloquial coding of みたい against ようだ's written / formal coding. (limitation) Pedagogy blog; used only as corroboration for register split. ↩ ↩²