LESSON NOTES · レッスンノート

N4Grammar, one piece at a time · Sep 14, 2026

〜やすい and 〜にくい: easy to do, hard to do, and prone to happening

Attach やすい or にくい to the ます-stem of a verb and you build a brand-new い-adjective: 読よみやすい (easy to read), 食たべにくい (hard to eat). The catch is that やすい has a second meaning — "prone to" — and 壊こわれやすい does not mean something is easy to break on purpose.

This is one of the highest-value grammar points at N4, because it turns every verb you know into two adjectives. Learners who have it produce natural sentences that would otherwise need a whole clause.

The basics

How do you build it?

Take the ます-form, drop ます, add やすい or にくい.

Verb ます-form + やすい + にくい
読よむ 読よみます 読よみやすい 読よみにくい
使つかう 使つかいます 使つかいやすい 使つかいにくい
分わかる 分わかります 分わかりやすい 分わかりにくい
食たべる 食たべます 食たべやすい 食たべにくい
する します しやすい しにくい

この本ほんは読よみやすいです。 — This book is easy to read. (polite) この漢字かんじは覚おぼえにくいです。 — This kanji is hard to remember. (polite)

The dictionary form does not work here. 読よむやすい is wrong — it has to be the stem, 読よみ. If you can make the ます-form, you can make this.

The result is an い-adjective

This is the part that unlocks everything. 読よみやすい behaves exactly like 高たかい or 安やすい:

前まえの携帯けいたいの方ほうが使つかいやすかったです。 — My old phone was easier to use. (polite past — やすい took かった) 字じが小ちいさくて読よみにくくないですか。 — Isn't the text hard to read, being so small? (polite negative question)

So all your い-adjective conjugation transfers directly: 〜かった for past, 〜くない for negative, 〜くて to connect, 〜そう for "looks."

What can it attach to?

Almost any action verb. It sounds natural with verbs where difficulty is a real variable — reading, using, eating, saying, walking, remembering — and odd with verbs that are all-or-nothing.

このスプーンは食たべやすいです。 — This spoon is easy to eat with. (polite — note the tool, not the food, is the subject) 雨あめの日にちは歩あるきにくいです。 — It's hard to walk on rainy days. (polite)

Beyond the basics

やすい also means "prone to," and that's a different idea

Here's the trap. With verbs that describe things happening to something rather than actions you choose, やすい means "tends to" or "easily happens":

このコップは壊こわれやすいです。 — This cup breaks easily. (polite — fragile, not "easy to break on purpose") 冬ふゆは風邪かぜをひきやすいです。 — You catch colds easily in winter. (polite) この服ふくはしわになりやすい。 — These clothes wrinkle easily. (casual)

Same ending, different meaning: the first sense is "easy for me to do," the second is "likely to happen." Which one you get is decided by the verb, not by the grammar. Intransitive or spontaneous verbs (壊こわれる, ひく a cold, 汚よごれる, 忘わすれる) give you "prone to."

にくい does the reverse: 壊こわれにくい means "durable," 汚よごれにくい means "stain-resistant." Japanese product packaging is full of these.

にくい vs づらい: hard for anyone, or hard for me?

Both mean "difficult to." The split is subtle but real, and native speakers feel it:

Form Feel Typical use
〜にくい An objective property of the thing この字じは読よみにくい
〜づらい Discomfort for the speaker 足あしが痛いたくて歩あるきづらい
〜がたい Nearly impossible; formal, literary 信しんじがたい話はなし

言いいにくいことなんですが… — This is a hard thing to say, but… (polite — socially awkward, the classic bad-news opener) 喉のどが痛いたくて話はなしづらいです。 — My throat hurts, so it's uncomfortable to talk. (polite — physical discomfort, personal)

づらい comes from 辛つらい (painful), which is why it leans toward "it hurts me to do this." がたい is written 難がたい and appears mostly in set phrases: 信しんじがたい (hard to believe), 理解りかいしがたい (hard to comprehend), ありがたい (thankful — literally "hard to exist," i.e. rare and precious).

The social 言いいにくい

言いいにくい is worth calling out on its own, because it does enormous work in Japanese conversation. It means "hard to say" in the awkward sense, and it is how people open difficult topics:

ちょっと言いいにくいんですけど、明日あした行いけません。 — This is a bit awkward to say, but I can't come tomorrow. (polite — softening a refusal)

Paired with the explanatory んです and a trailing けど, it is a complete apology structure before you have said anything at all.

What about "easy" as in simple?

やすい is not 簡単かんたん. 簡単かんたん describes the task itself as uncomplicated; やすい describes it as low-friction for the doer.

この問題もんだいは簡単かんたんです。 — This question is easy. (the problem is not difficult)

読よみやすい字じ is handwriting that doesn't strain your eyes; 簡単かんたんな字じ is a kanji with few strokes. Different claims.

Common mistakes

  • Using the dictionary form. 読よむやすい, 食たべるにくい — both wrong. Use the ます-stem: 読よみやすい, 食たべにくい.
  • Forgetting it conjugates. 読よみやすいでした is wrong; it's 読よみやすかったです, because やすい is an い-adjective now.
  • Reading 壊こわれやすい as "easy to break." It means fragile. Nobody is planning to break it.
  • Using にくい for personal discomfort. 足あしが痛いたくて歩あるきにくい is understandable, but 歩あるきづらい is what a native speaker says when their own foot hurts.
  • Confusing にくい with 憎にくい. They're homophones — 憎にくい means "hateful." Context separates them completely, but the kanji are different (難がたい vs 憎にくい), and the grammar one is normally written in kana.

Practice

Answers are hidden — build yours first, then open. Questions 5 and 6 are a pair: the same ending, two different meanings.

1. Make "easy to read" from 読よむ.

Show answer

読よみやすい — ます-form 読よみます, drop ます, add やすい. The dictionary form does not work.

2. Something is wrong here: この漢字かんじは覚おぼえるにくいです。

Show answer

覚おぼえにくいです — the stem is 覚おぼえ, from 覚おぼえます. Never the dictionary form.

3. Something is wrong here: 前まえの携帯けいたいは使つかいやすいでした。

Show answer

使つかいやすかったです — やすい is an い-adjective, so the past is かった. でした does not attach to い-adjectives.

4. Say "isn't this hard to read?" politely.

Show answer

読よみにくくないですか — the negative of an い-adjective: くない. Then ですか for the question.

5. What does このコップは割われやすいです mean?

Show answer

"This cup breaks easily" — with a spontaneous verb, やすい means "prone to," not "easy to do on purpose."

6. What does このスプーンは食たべやすいです mean?

Show answer

"This spoon is easy to eat with" — with a chosen action, やすい means low effort for the doer. This is the pair to question 5: the verb decides which meaning you get.

7. Your throat hurts and talking is uncomfortable. にくい or づらい?

Show answer

話はなしづらい — づらい comes from 辛つらい and covers personal discomfort. にくい describes a property of the thing itself.

8. Open a refusal softly, using 言いいにくい.

Show answer

ちょっと言いいにくいんですけど… — 言いいにくい is the socially awkward "hard to say," and the んですけど leaves the sentence open so the listener can help you finish it.

9. What does 汚よごれにくい on a shirt label promise?

Show answer

Stain-resistant — にくい with a spontaneous verb means "does not easily happen." Product packaging uses this constantly.

10. What is the difference between 読よみやすい字じ and 簡単かんたんな字じ?

Show answer

Legible handwriting vs a simple character — やすい is about low friction for the reader; 簡単かんたん is about the thing itself being uncomplicated.

FAQ

Can I use these with する verbs? Yes: 勉強べんきょうしやすい, 説明せつめいしにくい. The stem of します is し, so it attaches cleanly.

Do they work with the potential form? Not usually — 読よめやすい is not natural. Difficulty and ability are separate ideas; use できる for ability and やすい/にくい for how much effort something takes.

Is にくい ever written in kanji? It can be written 難がたい, but kana is far more common for the grammatical use, partly to avoid confusion with 憎にくい.

What is the negative of 読よみやすい? 読よみやすくない ("not easy to read"). Note that this is not the same as 読よみにくい ("hard to read") — the first denies ease, the second asserts difficulty, and the second is stronger.

Are there fixed words built from this? Plenty: 分わかりやすい (clear), 使つかいやすい (user-friendly), ありがたい (grateful), 忘わすれやすい (forgetful). They function as ordinary vocabulary.

Can it attach to adjectives? No — verbs only. For "easily becomes cold," you'd verbalise it first: 冷さめやすい.

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab — the first column becomes the front, the second the back.

読む	よむ — to read
使う	つかう — to use
分かる	わかる — to understand
覚える	おぼえる — to remember, to learn
食べる	たべる — to eat
歩く	あるく — to walk
言う	いう — to say
話す	はなす — to speak
漢字	かんじ — kanji
携帯	けいたい — mobile phone
字	じ — character, handwriting
小さい	ちいさい — small
壊れる	こわれる — to break
割れる	われる — to crack, to shatter
風邪	かぜ — a cold
汚れる	よごれる — to get dirty
喉	のど — throat
足	あし — leg, foot
痛い	いたい — painful
簡単	かんたん — easy, simple
問題	もんだい — problem, question
冬	ふゆ — winter
服	ふく — clothes
説明	せつめい — explanation

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime. When a learner says 簡単かんたんに掃除そうじできる and I offer 掃除そうじしやすい instead, you can watch the idea land — one ending, and every verb they own turns into two more adjectives.

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Sources: the author's own lessons and standard reference grammars.

More drills like the ones above, plus a timed JLPT-style mock test: Practice · N4

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