目錄
When reading Japanese news articles or working through N1 reading-comprehension questions, you will often come across expressions such as 「想像に難くない」 or 「理解するに難くない」. Taken literally, translating them as “not difficult to imagine” or “easy to understand” seems fairly straightforward. But when you actually try to use the pattern in your own writing or apply it to other sentences, things quickly become less simple. What makes this grammar especially difficult to grasp is not that its meaning is particularly obscure, but that the range of words it can attach to is astonishingly narrow. Unlike versatile grammar patterns that can be freely combined with almost any verb, this expression is tied to only a small group of specific words related to inference and understanding. Pair it with another kind of action, and the entire sentence will sound noticeably unnatural. Understanding the boundaries of these fixed combinations is what makes it possible to immediately catch the analytical nuance often found in more formal commentary—the sense that a conclusion is “reasonable even without being stated explicitly.”
Nuance Restrictions of Japanese 「に難くない」: Why Can It Only Be Used with Certain Mental-Process Words?
Literally, 「に難くない」 contains 「難くない（not difficult）」, but it is not a general-purpose expression meaning “it is not difficult to do something.” Instead, it is specifically used with mental activities involving inference, understanding, or imagination, as in 「想像に難くない」 and 「理解するに難くない」. This restriction makes it a formal, fixed expression characteristic of written language. It is commonly found in newspaper commentary, academic writing, and formal reports, where it indicates that a particular conclusion can be readily inferred from the information already available, rather than describing the difficulty of performing a concrete action.
How Is 「に難くない」 Used? Core Functions and Attachment Rules
Attachment Rules
The way 「に難くない」 attaches is simple, but its range of use is strictly limited. It can only follow words related to inference and understanding, such as 「想像、推察、予想、予測、理解、察する、知る」. Even other verbs with similar meanings cannot necessarily be inserted freely into this pattern.
| Type of word | Attachment pattern | Example |
| Noun（stem of a する verb） | noun＋に難くない | 想像に難くない |
| Verb（する form） | verbする＋に難くない | 理解するに難くない |
Usage ① of 「に難くない」｜Expressing That Something Is Not Difficult to Infer or Understand
This usage applies when the speaker judges, on the basis of the current situation or available information, that something is “not difficult to imagine” or “not difficult to understand.” It has a formal, analytical tone associated with written language and is often used in opening or concluding statements in commentary.
- Example: 彼女が初めての一人暮らしで寂しい思いをしているだろうことは想像に難くない。
Translation: It is not difficult to imagine that she must feel lonely living alone for the first time.
Here, 「想像に難くない」 sums up the situation described beforehand and indicates that the reader can readily infer this conclusion from common sense alone. This is a typical way of closing an analytical or commentary-style passage. - Example: そのニュースを聞いて、彼の悲しみを理解するに難くない。
Translation: After hearing that news, it is not difficult to understand his sadness.
Here, 「理解するに難くない」 expresses the speaker’s ability to empathize with another person’s emotions while also implying that there is sufficient basis for that understanding and that no further explanation is really necessary. - Example: この先の人生の難しさは察するに難くない。
Translation: It is not difficult to infer how difficult life will be from this point onward.
Here, 「察するに難くない」 expresses an inference about someone’s future circumstances, with a sense of tacit understanding that “you can tell without being told.” This attitude of making a judgment because there is sufficient basis for it also shares something in common with the logic behind the inferential expression 「はず」.
Usage ② of 「に難くない」｜Expressing That Something Is Not Difficult to Predict or Infer
This usage focuses on “predicting the future based on data, trends, or the current situation.” It is often paired with words such as 「予測する」 and 「予想する」 and tends to sound rational and analytical, making it common in economic commentary, discussions of social issues, and similar writing.
- Example: 日本経済は低出生率と高齢化により低迷が続くことは予想するに難くない。
Translation: Given the low birth rate and aging population, it is not difficult to expect that Japan’s economy will remain sluggish.
Here, 「予想するに難くない」 summarizes factors such as the low birth rate and aging population mentioned earlier and indicates that arriving at the conclusion that “economic stagnation will continue” is not difficult. - Example: 会社社長の立場から考えれば、彼が下した経営判断は理解するに難くない。
Translation: From the standpoint of a company president, it is not difficult to understand the management decision he made.
This sentence places “understanding” within the premise of considering the situation from a company president’s perspective. It suggests that once you put yourself in that position, the logic of the decision becomes easy to understand. - Example: このデータから、今後の需要が拡大することは予測に難くない。
Translation: From this data, it is not difficult to predict that demand will expand in the future.
Here, 「予測に難くない」 summarizes the conclusion drawn from the data analysis. The tone is rational and is commonly seen in the concluding sections of business reports or market-analysis articles.
What Is the Difference Between Japanese 「に難くない」, 「がたい」, and 「にくい」?
All three expressions contain the character 「難」, but their functions are completely different. One means “not difficult to infer or understand,” another expresses something that is emotionally difficult to bring oneself to do or realize, and the third describes something that is difficult to do because of some practical reason. Their similar appearance makes them easy to confuse.
| Comparison point | に難くない | がたい | にくい |
| Core meaning | Not difficult to infer or understand | Difficult to do or realize because of emotion or circumstances | Difficult to do because of some reason |
| Range of attachment | Extremely restricted（specific words such as 想像 and 理解） | Limited（verb ます-stem; only a limited set are common） | Broad（can attach to almost any verb ます-stem） |
| Nuance | Written, analytical, formal | Written, emotionally charged | Used in both speech and writing; describes concrete obstacles |
| Common mistake | ❌ Applying it to arbitrary verbs | ❌ Using it for simple physical difficulty | ❌ Assuming it has the same nuance as がたい |
| Correct example | ✅ 想像に難くない | ✅ 忘れがたい思い出 | ✅ 字が小さくて読みにくい |
▌The Core Difference Between 「に難くない」 and 「がたい」
❌ Incorrect: この漢字は難くない。（「に難くない」 cannot simply follow an ordinary noun to mean “not difficult.” It can only be used with certain words related to inference or understanding, so this usage is incorrect）
✅ Correct: この漢字を忘れがたい。（If you want to express the emotional sense of something being difficult to forget, you should use 「がたい」, as in 「忘れがたい思い出（an unforgettable memory）」）
「に難くない」 means that something is not difficult to infer or understand, while 「がたい」 means that something is difficult to carry out or realize because of one’s emotions or circumstances, even if one wants to do it. Although both contain the character 「難」, one concerns the ease of inference while the other concerns difficulty in realization, so their meanings point in completely different directions.
▌The Core Difference Between 「に難くない」 and 「にくい」
❌ Overgeneralization: Assuming that both 「に難くない」 and 「にくい」 can freely attach to many different verbs.
✅ Correct understanding: 「にくい」 has a broad range of attachment and can be added to the ます-stem of almost any verb to describe practical or perceptual difficulty, as in 「読みにくい（hard to read）」 and 「歩きにくい（hard to walk）」. In contrast, 「に難くない」 has an extremely narrow range of use and is limited to words related to mental activities such as imagining, understanding, and inferring.
「にくい」 deals with concrete, practical difficulty, whereas 「に難くない」 deals with the ease of abstract reasoning. In this sense, its strongly written character and relatively weighty tone give it some similarities to advanced N1/N2 grammar such as 「ずにはいられない」, but their ranges of use and nuances are completely different. They should not be treated as the same kind of expression simply because both contain the character 「難」.
「に難くない」 in Japanese Conversation and Written Language: Features of Its Use in News Commentary and Court Judgments
In Japanese newspaper commentary, editorials, and court judgments, writers often present a series of facts or data and then use expressions such as 「に難くない」 to summarize a conclusion as “obvious” or readily inferable. This allows them to state their own judgment without sounding excessively assertive, because the phrasing implies that “this is a reasonable inference anyone could reach from the available information,” rather than merely the writer’s personal speculation.
▌Situation ①｜Editorial Staff Discussing How to End a Commentary Article
A：この記事の締めくくり、「今後の政策変更は避けられないと考えるに難くない」でどうでしょう。
このきじのしめくくり、「こんごのせいさくへんこうはさけられないとかんがえるにかたくない」でどうでしょう。
How about ending the article with, “It is not difficult to conclude that future policy changes will be unavoidable”?
B：いいですね。断定しすぎず、それでいて説得力がある表現です。
いいですね。だんていしすぎず、それでいてせっとくりょくがあるひょうげんです。
That sounds good. It avoids sounding too categorical while still being persuasive.
📌 Grammar Point: 「考えるに難くない」 allows a writer to present a personal judgment as a “reasonable inference” when concluding a commentary piece. It avoids giving readers an overly categorical impression while still communicating the writer’s position clearly, making it a common type of closing expression in editorials.
▌Situation ②｜Coworkers Discussing Why a Manager Made a Decision
A：部長があの案を却下した理由は、理解するに難くないよ。
ぶちょうがあのあんをきゃかしたりゆうは、りかいするにかたくないよ。
It is not hard to understand why the department manager rejected that proposal.
B：確かに、予算の面から見ても妃当な判断だったと思う。
たしかに、よさんのめんからみてもだとうなはんだんだったとおもう。
True. Even from the budget perspective, I think it was a reasonable decision.
📌 Grammar Point: Here, 「理解するに難くない」 expresses the idea that “once you put yourself in the other person’s position, the decision actually makes sense.” Compared with simply saying “I understand,” it gives a stronger sense that the understanding comes after rational analysis of the other party’s position.
Cultural Notes:
- Japanese court judgments often contain expressions such as 「〜と推認するに難くない」 to indicate that the judge has reasonably inferred a conclusion from existing evidence rather than relying on baseless speculation. This type of wording reinforces the logical legitimacy of the judgment.
- 「に難くない」 is hardly ever used in ordinary everyday conversation because its nuance belongs strongly to formal, analytical written language. Using it while casually chatting with friends can therefore sound deliberate and stiff.
- This grammar also appears frequently in commentary passages in N1 reading-comprehension tests. If learners can recognize 「〜に難くない」 as a fixed expression meaning that “the conclusion is obvious or readily inferable,” they can often grasp the main line of argument more quickly.
How Does Japanese 「に難くない」 Compare with Korean 「짐작하기 어렵지 않다」?
The Korean expression 「짐작하기 어렵지 않다」 likewise means “it is not difficult to infer or guess.” The dictionary form of the verb is 「짐작하다（斤酣, inference）」, which combines with the fixed pattern 「-기 어렵지 않다」 meaning “it is not difficult to…”. Functionally, it is highly similar to 「に難くない」.
- Example: 그의 마음이 얼마나 힘들었을지 짐작하기 어렵지 않다.
Romanization: geu-ui ma-eum-i eol-ma-na him-deul-eoss-eul-ji jim-jak-ha-gi eo-ryeop-ji an-ta.
Translation: It is not difficult to imagine how difficult things must have been for him emotionally.
The structure of this sentence is almost identical to 「想像に難くない」. Both first describe a situation and then conclude with “it is not difficult to infer,” showing that the conclusion is readily apparent. - Example: 이런 상황에서 그가 왜 그런 결정을 내렸는지 충분히 짐작할 수 있다.
Romanization: i-reon sang-hwang-e-seo geu-ga wae geu-reon gyeol-jeong-eul nae-ryeoss-neun-ji chung-bun-hi jim-jak-hal su it-da.
Translation: In this situation, it is entirely possible to infer why he made that decision.
This expression, 「칩분히 짐작할 수 있다（entirely possible to infer）」, has a similar nuance to 「に難くない」 in that both emphasize that “this inference is not far-fetched.”
◆ Core difference from 「に難くない」:
The Korean expression 「짐작하기 어렵지 않다」 is more flexible in what it can attach to than Japanese 「に難くない」 and can be used with a wider range of verbs related to inference. By contrast, Japanese 「に難くない」 is restricted to a small set of fixed words such as 「想像、推察、理解、予測、予想、察する、知る」. This is why Japanese learners often memorize 「に難くない」 as a group of fixed collocations rather than treating it as a freely productive grammar rule.
Once you understand the restrictions on 「に難くない」, expressions such as 「がたい」 and 「にくい」—which look similar and also contain the character 「難」—become much easier to organize conceptually. This advanced grammar pattern is almost never useful when chatting with Japanese friends or sending casual messages, but it is an important key to understanding Japanese editorials, in-depth reporting, and even court judgments. Learning grammar is not just about memorizing translations. If you separate out these fixed expressions with extremely narrow attachment ranges, you are less likely to get stuck in the same place repeatedly when speaking or writing, and you can also identify the rational, analytical tone a writer is trying to convey much more quickly when reading.
FAQs
「に難くない」 means “not difficult to…” or “easy to…”. It is used to indicate that a particular conclusion can be readily inferred or understood from the current situation or available information. The expression is formal and is commonly found in the concluding sentences of commentary or reports.
It can only follow certain words related to inference and understanding, such as 「想像、推察、察する、予測、予想、理解、知る」. It cannot be freely applied to other verbs and is therefore a restricted fixed expression.
「に難くない」 means that something is not difficult to infer or understand, whereas 「がたい」 indicates that something is difficult to do or realize because of emotional or situational factors. Although both contain the character 「難」, their meanings point in completely different directions and they cannot be used interchangeably.
「にくい」 has a broad range of attachment and is used to describe concrete operational or perceptual difficulty, whereas 「に難くない」 has an extremely restricted range and is used only to express the ease of abstract reasoning. They operate on completely different levels.
In addition to newspaper commentary, 「に難くない」 is often seen in court judgments（such as 「〜と推認するに難くない」）, academic papers, and the concluding sections of business-analysis reports. It is suitable for formal written contexts where the writer needs to summarize a conclusion as an “obvious inference.”