At the A1 level, you can think of '有効な' (yūkō na) as a word that means 'good' or 'working.' Imagine you have a ticket for a bus. If the bus driver looks at it and says 'OK,' the ticket is 'yūkō.' It is a bit like saying 'Yes, this is still a good ticket.' You might not use this word yourself very much yet, but you will see it on signs. For example, a sign might say 'Today only yūkō,' which means you can only use it today. It's a very useful word for traveling. Just remember that it is used for things like tickets, coupons, and rules. It's not usually used for people. If you want to say a person is good, you use 'ii' or 'shinsetsu.' 'Yūkō' is for things that have a purpose or a date. When you see the kanji 有, think of 'having' or 'existing,' and when you see 効, think of 'power' or 'working.' So, it means 'having the power to work.' At this stage, just focus on the 'valid' meaning. If a teacher gives you a coupon for a free sticker, and you can still use it, it is 'yūkō.' If it is too old, it is 'mukō' (not yūkō). Keeping it simple will help you recognize it when you travel in Japan.
At the A2 level, you can start using '有効な' (yūkō na) to describe things more clearly. You are learning that Japanese has special words for 'valid' and 'effective.' 'Yūkō' is a 'na-adjective,' so you say 'yūkō na' before a noun. For example, 'yūkō na pasupōto' means 'a valid passport.' This is very important for travel and shopping. You might also hear this word in basic health contexts, like 'yūkō na kusuri' (effective medicine). At this level, you should try to remember the opposite word, 'mukō' (invalid). If your credit card doesn't work, the shop staff might say it is 'mukō.' You can also use 'yūkō' to talk about time. 'Jikan o yūkō ni tsukaimashō' means 'Let's use time effectively.' This is a common phrase in schools and offices. You are starting to see that 'yūkō' is more formal than just saying 'ii' (good). It sounds more professional. When you are writing a simple email to a Japanese friend about a meeting, you could say 'Kono hi wa yūkō desu ka?' (Is this day valid/good for you?), though 'daijōbu' is more common. 'Yūkō' is best kept for things with rules or dates. Focus on using it with nouns like 'ticket' (kippu), 'date' (kigen), and 'method' (hōhō). This will make your Japanese sound more precise and advanced than a beginner's.
At the B1 level, '有効な' (yūkō na) becomes a key part of your vocabulary for business, legal, and social discussions. You should now understand the two main branches of its meaning: 'validity' and 'effectiveness.' In terms of validity, you will use it for contracts (keiyaku), visas (biza), and identification (mibun shōmeisho). For example, 'Kono keiyaku wa go-nenkan yūkō desu' (This contract is valid for five years). In terms of effectiveness, you will use it to describe strategies and solutions. A 'yūkō na taisaku' is an effective measure or countermeasure against a problem. You are also expected to use the adverbial form 'yūkō ni' to describe how actions are performed. 'Shigen o yūkō ni katsuyō suru' (To utilize resources effectively) is a typical B1-level sentence. You should be able to distinguish 'yūkō' from 'kōka-teki' (effective/impactful). Remember that 'yūkō' often implies that something is 'active' or 'legitimate' within a system, while 'kōka-teki' is about the impression or result. At this level, you might also encounter the noun form 'yūkō-sei' (efficacy/validity) in news reports. For example, discussing the 'yūkō-sei' of a new law. Being able to use this word in a variety of contexts—from checking your passport's expiration date to suggesting a better way to study—shows that you have reached an intermediate level of Japanese proficiency. It is a word that appears frequently on the JLPT N3 exam, so mastering its nuances is crucial for your progress.
For B2 learners, '有効な' (yūkō na) is a word that requires precision in both formal writing and professional speaking. You should be comfortable using it in complex sentence structures, such as 'Kono shudan wa, genzai no jōkyō ni oite mottomo yūkō da to kangaerareru' (This method is considered the most effective in the current situation). At this level, you should explore the economic and statistical uses of the word. For instance, 'yūkō kyūjin bairitsu' (the active job openings-to-applicants ratio) is a term you will see in newspapers and business reports. You should also understand the nuance of 'yūkō' in competitive contexts, like 'yūkō-da' (an effective blow or scoring point) in sports or debates. This implies not just that something worked, but that it was a 'valid' point within the rules of the game. You should be able to explain the difference between 'yūkō' and 'kōritsu' (efficiency) in a business presentation. 'Yūkō' is about doing the right things (effectiveness), whereas 'kōritsu' is about doing things in the right way (efficiency). In legal contexts, you should know how 'yūkō' relates to 'shikkō' (expiration/loss of validity). If a right or a contract is no longer 'yūkō,' it has 'shikkō' (lapsed). Your ability to use 'yūkō' to discuss policy efficacy, document validity, and resource management with native-like accuracy is a hallmark of the B2 level. You should also be able to use the word in the passive or causative forms if necessary, such as 'yūkō ni saseru' (to make something effective/valid).
At the C1 level, your understanding of '有効な' (yūkō na) should extend into the realms of legal philosophy, advanced economics, and nuanced rhetoric. You should be able to discuss the 'validity' of an argument not just as 'correct,' but as 'yūkō' within a specific logical framework. In legal Japanese, 'yūkō' is often contrasted with 'torikeshi-ubeki' (voidable) or 'mukō' (void ab initio). You should understand how 'yūkō' functions in the 'Minpō' (Civil Code) regarding the validity of wills, contracts, and marriages. Furthermore, you should be able to use 'yūkō' in abstract discussions about time and existence. For example, 'yūkō na jinsei' (a meaningful/effective life) suggests a life lived with purpose and impact. In academic writing, you will use 'yūkō-sei' to analyze the validity of research methodologies or the efficacy of clinical trials. You should also be aware of the historical development of the term and its usage in various professional 'jargon.' For example, in computer science, 'yūkō na dēta' (valid data) refers to data that meets specific validation criteria. Your usage should reflect a deep awareness of register; you know when 'yūkō' is too clinical and when it provides the necessary weight to a formal statement. You can seamlessly integrate it into high-level debates about 'yūkō na shigen haibun' (effective resource allocation) in the context of global environmental issues or economic policy. At this level, 'yūkō' is not just a word, but a tool for precise conceptual categorization.
At the C2 level, you possess a masterly command of '有効な' (yūkō na), utilizing it with the same subtlety and range as a highly educated native speaker. You understand its role in the finest points of Japanese law, where the distinction between 'yūkō' (valid), 'tekihō' (legal), and 'datō' (appropriate) can determine the outcome of a case. You can engage in deep philosophical discourse on the 'yūkō-sei' of social contracts or the 'yūkō-sei' of language itself as a means of communication. In literary contexts, you might analyze how an author uses the concept of 'validity' or 'effectiveness' to critique modern society. You are also familiar with archaic or highly specialized uses of the kanji 効 in classical Japanese texts, which informs your understanding of the modern word's weight. Your ability to pun or use the word ironically in sophisticated social settings is also developed. You can critique the 'yūkō-sei' of a government's 'yūkō kyūjin bairitsu' statistics, understanding the underlying economic complexities and how the data is gathered. In professional environments, you use 'yūkō' to navigate complex negotiations, ensuring that every agreement is 'yūkō' and 'shikkō' (enforceable). You are a master of the adverbial 'yūkō ni,' using it to describe the elegant and masterful application of skills or resources. For a C2 learner, '有効な' is a multifaceted diamond of a word, reflecting different meanings and nuances depending on the light of the context in which it is placed. You use it with effortless precision, whether drafting a legal document, writing a scientific paper, or engaging in high-level political analysis.

有効な 30秒了解

  • Means 'valid' or 'effective.' Used for documents like passports and methods like strategies.
  • It is a na-adjective, so use 'na' before nouns (e.g., yūkō na hōhō).
  • Commonly found in business, travel, and legal contexts in Japan.
  • Opposite is 'mukō' (invalid). It is more formal than 'ii' (good).

The Japanese word 有効な (yūkō na) is a versatile 'na-adjective' that serves as a cornerstone for describing things that are functional, legally valid, or practically effective. At its linguistic core, it is composed of two kanji: (existence/possession) and (effect/efficacy). Together, they literally mean 'possessing an effect.' This word is essential for English speakers because it covers ground that English often splits between 'valid' (like a passport) and 'effective' (like a strategy). In Japan, you will encounter this word in every facet of life, from bureaucratic procedures to sports commentary and business meetings.

Legal Validity
This is perhaps the most common use. When a document, such as a driver's license, a coupon, or a passport, is within its expiration date and legally recognized, it is described as yūkō. If you are at an airport and the official says your visa is 'yūkō,' it means you are good to go.

このパスポートは来年まで有効な書類です。 (This passport is a valid document until next year.)

Practical Efficacy
Beyond legalities, it describes methods or measures that actually work. If a company implements a new policy that successfully reduces waste, that policy is called a yūkō na saku (an effective measure). It implies that the action taken has produced the intended result.

The word is also used in the context of 'effective utilization' (yūkō katsuyō). For instance, finding a productive use for an empty lot or making the best use of one's limited free time. This nuance of 'not letting something go to waste' is a key part of the Japanese mindset. Whether you are talking about a medicine that is effective against a virus or a coupon that gives you a discount, yūkō na is the go-to term for asserting that something still 'has its power' or 'is working as intended.' It is a formal yet accessible word that bridges the gap between everyday conversation and professional documentation.

Using 有効な correctly requires understanding its role as a na-adjective. This means that when it modifies a noun directly, you must include the 'na' particle. For example, 'effective method' becomes yūkō na hōhō. If you are using it at the end of a sentence to describe a subject, you use 'da' or 'desu' instead of 'na,' as in kono ken wa yūkō desu (this ticket is valid).

時間を有効な方法で使いましょう。 (Let's use time in an effective way.)

Modifying Nouns
When placed before a noun: [有効な] + [Noun]. Common pairings include yūkō na shudan (effective means), yūkō na kikan (valid period), and yūkō na riyō (effective use).

In more advanced contexts, yūkō can be combined with other words to create compound nouns. For example, yūkō-kigen means 'expiration date' or 'validity period.' In these cases, the 'na' is dropped because it is functioning as part of a compound noun phrase. You will see this on food packaging, credit cards, and official forms. Understanding when to keep the 'na' and when it becomes part of a larger noun is a key step in mastering B1-level Japanese grammar.

この対策は非常に有効だと判断されました。 (It was judged that this measure is extremely effective.)

When talking about validity, the word often appears in the negative form: mukō (invalid). If a contract is no longer in effect, it becomes mukō. Learning these as a pair—yūkō for 'active/valid' and mukō for 'void/invalid'—will help you navigate legal and formal situations in Japan much more effectively. Always pay attention to the context: is the speaker talking about the 'legitimacy' of something or its 'usefulness'? While yūkō na covers both, the English translation will shift depending on the situation.

You will hear 有効な in a variety of real-world Japanese environments. It is not just a textbook word; it is deeply embedded in daily life. One of the most common places is at the station or airport. Announcements regarding ticket validity or the status of travel documents frequently use this term. For instance, if a special rail pass is only valid on certain lines, the staff might explain the 'yūkō na han-i' (the valid range/area) of the pass.

このクーポンは、本日のみ有効なものです。 (This coupon is valid for today only.)

In the Business World
In meetings, managers often discuss yūkō na tōshi (effective investment) or yūkō na jikan no tsukaikata (effective way to use time). It carries a professional nuance that suggests efficiency and strategic thinking. If you suggest a 'yūkō na hōhō' (effective method) in a meeting, you sound competent and focused on results.

In the news and media, yūkō is used to discuss government policies or medical breakthroughs. When a new vaccine is developed, news anchors will report on its yūkō-sei (efficacy rate). They might say, 'The vaccine was found to be 95% yūkō.' This technical use is very common in scientific and medical reporting. Additionally, in the context of employment, you might hear about the 'yūkō kyūjin bairitsu' (active job openings-to-applicants ratio), which is a major economic indicator in Japan.

空き家を有効な形で再利用するプロジェクトが始まりました。 (A project has started to reuse abandoned houses in an effective way.)

Finally, in sports like Judo or Karate, you might hear the referee shout 'Yuko!' Although the scoring systems change, the term historically indicated a 'valid' point-scoring action. Even outside of professional matches, people might use it jokingly when someone makes a good point in an argument, saying 'Yūkō-da ne!' (That’s a valid point/hit!). This broad range of usage—from the extremely formal to the slightly colloquial—makes it a vital word for any student reaching the intermediate level.

While 有効な is a powerful word, English speakers often stumble when choosing between it and other similar-sounding or similar-meaning Japanese words. The most common mistake is confusing yūkō with kōka-teki (effective). While they overlap, kōka-teki specifically refers to the *result* or the 'impact' something has. Yūkō is more about the 'validity' or the 'inherent power' of the method itself. For example, a medicine is yūkō (it has the active ingredients to work), and the treatment's result is kōka-teki (it had a good effect on the patient).

Confusing with 'Efficient'
Another pitfall is using yūkō when you actually mean kōritsu-teki (efficient). Kōritsu-teki is about the ratio of input to output—doing something quickly with little effort. Yūkō is about whether the thing works at all or is legally allowed. If you say a machine is yūkō, you mean it is still functional and valid to use; if you say it is kōritsu-teki, you mean it saves electricity or time.

Incorrect: このチケットは効果的です。
Correct: このチケットは有効です。 (This ticket is valid.)

Another mistake involves the 'na' particle. Since yūkō can also act as a noun (meaning 'validity' or 'effectiveness'), students sometimes forget to add 'na' when using it as an adjective. You cannot say 'yūkō hōhō'; it must be 'yūkō na hōhō.' Conversely, in compound words like yūkō-kigen (expiration date), adding 'na' would be wrong. It takes practice to feel when yūkō is acting as a standalone adjective versus a building block for a compound noun.

Lastly, be careful with the word 'valid' in the sense of 'a valid point' in a conversation. While you can use yūkō, it often sounds a bit stiff or technical. In a casual debate, Japanese speakers might prefer tōzen (naturally), motto mo (reasonable), or tashika ni (certainly). Use yūkō when you want to emphasize the strategic value or the formal legitimacy of the point being made, rather than just agreeing with it.

To truly master 有効な, you should understand its synonyms and how they differ in nuance. Japanese has many words for 'effective' or 'useful,' and choosing the right one depends on whether you are talking about results, efficiency, or simple utility.

有効 (Yūkō) vs. 効果的 (Kōka-teki)
有効: Focuses on validity and the inherent power to work. Used for contracts, visas, and strategic use of resources.
効果的: Focuses on the visible results or impact. Used for advertising, teaching methods, or medicine that has already shown results.
有効 (Yūkō) vs. 効率的 (Kōritsu-teki)
有効: Doing the 'right' thing that works.
効率的: Doing things 'right' (quickly/cheaply). An effective (yūkō) method might not be efficient (kōritsu-teki) if it costs too much money.

Alternative: 実用的な (Jitsuyō-teki na) - Practical. Use this for tools or advice that is easy to apply in real life.

Other alternatives include yūryoku na (powerful/influential), which is used for people or candidates who have a high chance of winning. If you want to say something is 'useful' in a general sense, yūki na (useful/helpful) is common. For something that is 'valid' in the sense of being 'legal,' you might also hear tekitō na (appropriate) or seishiki na (formal/official).

In summary, while yūkō na is the most versatile term for 'valid and effective,' keep kōka-teki for results and kōritsu-teki for speed. If you are in a legal setting, yūkō is indispensable. If you are in a workshop, jitsuyō-teki might be better. By learning these distinctions, you move beyond simple translation and begin to think in Japanese nuances.

How Formal Is It?

趣味小知识

The kanji 効 contains the radical for 'strength' (力), implying that effectiveness requires power or effort.

发音指南

UK /juːkoʊ/
US /juːkoʊ/
Yū-KŌ (The 'ko' is often slightly emphasized in standard Tokyo Japanese).
押韵词
Kōkō (High school) Ryōkō (Travel) Tōkō (Posting) Hōkō (Direction) Chōkō (Sign) Sōkō (Armor) Kyōkō (Enforcement) Bōkō (Violence)
常见错误
  • Pronouncing the 'u' and 'o' as short vowels. It's not 'yuko' like a name, but 'yū-kō'.
  • Confusing the pitch with 'yūko' (a common female name).

难度评级

阅读 3/5

The kanji are common but require intermediate knowledge. Often seen on official documents.

写作 4/5

Writing '効' can be tricky for beginners due to the number of strokes.

口语 2/5

Easy to pronounce once you master the long vowels.

听力 3/5

Must distinguish from similar sounding words like 'yūko' (name) or 'yūno' (talented).

接下来学什么

前置知识

有る (aru) 効く (kiku) 方法 (hōhō) 時間 (jikan) チケット (chiketto)

接下来学习

効果 (kōka) 効率 (kōritsu) 無効 (mukō) 期限 (kigen) 活用 (katsuyō)

高级

効力 (kōryoku) 失効 (shikkō) 妥当 (datō) 法的 (hōteki) 契約 (keiyaku)

需要掌握的语法

Na-adjective modification

有効な方法 (Effective method)

Adverbial 'ni' form

有効に使う (Use effectively)

'Desu/Da' for state of being

このカードは有効だ (This card is valid)

Compound noun formation

有効期限 (Validity period - no 'na')

Negative form 'de wa nai'

有効ではない (Not valid)

按水平分级的例句

1

このチケットは有効ですか?

Is this ticket valid?

'Yūkō' is used here with 'desu' to ask about validity.

2

今日は有効なカードがあります。

I have a valid card today.

'Yūkō na' modifies the noun 'kādo' (card).

3

有効な日は明日です。

The valid day is tomorrow.

'Yūkō na' modifies 'hi' (day).

4

これは有効なクーポンです。

This is a valid coupon.

Simple 'A is B' structure with a na-adjective.

5

そのパスは有効じゃないです。

That pass is not valid.

Negative form 'yūkō janai' (informal/neutral).

6

有効な時間を使いましょう。

Let's use valid (available) time.

In A1, this is a simple way to say 'useful time.'

7

有効な番号を教えてください。

Please tell me a valid number.

'Yūkō na' used for a 'working' number.

8

有効なルールを守ります。

I will follow the valid rules.

'Yūkō na' modifying 'rūru' (rules).

1

有効なパスポートを持ってきました。

I brought a valid passport.

Standard na-adjective usage.

2

この薬は風邪に有効なはずです。

This medicine should be effective for a cold.

'Hazu' expresses expectation of effectiveness.

3

時間を有効に使いたいですね。

I want to use time effectively, don't I?

Adverbial 'yūkō ni' with the verb 'tsukau' (use).

4

有効な方法を教えてください。

Please tell me an effective method.

Requesting a 'working' way to do something.

5

そのチケットはもう有効ではありません。

That ticket is no longer valid.

Formal negative 'yūkō de wa arimasen.'

6

有効な手段を選びましょう。

Let's choose an effective means/way.

'Shudan' is a common noun paired with 'yūkō.'

7

新しい有効なルールができました。

A new, effective rule was made.

Two adjectives modifying 'rūru.'

8

このカードはいつまで有効ですか?

Until when is this card valid?

Asking about the 'yūkō kigen' (expiration).

1

政府は有効な対策を立てるべきだ。

The government should establish effective measures.

'Taisaku' (measures) is a high-frequency B1 noun.

2

空いている土地を有効に活用する。

To effectively utilize vacant land.

'Katsuyō suru' is a formal way to say 'use.'

3

この契約は来月末まで有効な状態です。

This contract is in a valid state until the end of next month.

'Yūkō na jōtai' (valid state) adds detail.

4

有効な意見があれば、言ってください。

If you have any valid/effective opinions, please say so.

'Yūkō na' applied to abstract ideas.

5

彼は有効なアドバイスをくれた。

He gave me effective advice.

Using 'yūkō' to describe the quality of help.

6

そのシステムは非常に有効に機能している。

That system is functioning very effectively.

'Yūkō ni kinō suru' is a professional set phrase.

7

有効な身分証明書を見せてください。

Please show a valid ID card.

'Mibun shōmeisho' is standard for 'ID.'

8

この方法は、学習において有効な手段だ。

This method is an effective means for learning.

Topic marker 'wa' with a descriptive 'na' adjective.

1

この投資は、将来的に有効な選択となるだろう。

This investment will likely become an effective choice in the future.

Future conjecture with 'darō.'

2

有効な求人倍率が上昇している。

The active job openings-to-applicants ratio is rising.

'Yūkō kyūjin bairitsu' is a specific economic term.

3

資源を有効に配分することが求められている。

Effective allocation of resources is required.

Passive 'motomerarete iru' (is required).

4

その証言は裁判で有効な証拠となった。

That testimony became valid evidence in court.

'Shōko' (evidence) is a formal noun.

5

有効な解決策を見つけるのは難しい。

Finding an effective solution is difficult.

'Kaigetsu-saku' (solution) is a common B2 compound.

6

彼は時間の有効な使い方を熟知している。

He is well-versed in the effective use of time.

'Jukuchi suru' (to be well-versed) is advanced.

7

有効な期間内に手続きを完了させてください。

Please complete the procedures within the valid period.

'Kikan' (period) and 'tetsuzuki' (procedures).

8

最新の研究で、この成分の有効性が証明された。

In the latest research, the efficacy of this ingredient was proven.

'Yūkō-sei' (efficacy) is the noun form.

1

有効な憲法改正の議論が必要だ。

A valid/effective debate on constitutional reform is necessary.

Discussing high-level political concepts.

2

この文書は、署名がない限り有効なものとは見なされない。

This document is not considered valid unless it has a signature.

Conditional 'kagiri' and passive 'minasanai.'

3

彼は有効な一打を放ち、試合を決定づけた。

He landed an effective blow, deciding the match.

'Yūkō na ichida' (an effective strike).

4

データが有効な範囲を超えているため、再計算が必要だ。

Since the data exceeds the valid range, recalculation is necessary.

'Yūkō na han-i' (valid range) in a technical context.

5

有効な社会保障制度の維持が課題となっている。

Maintaining an effective social security system has become a challenge.

'Shakai hoshō seido' (social security system).

6

この理論は、特定の条件下でのみ有効なものだ。

This theory is valid only under specific conditions.

'Tokutei no jōken-ka' (under specific conditions).

7

有効なコミュニケーションを築くことが成功の鍵だ。

Building effective communication is the key to success.

Abstract usage for interpersonal skills.

8

その特許は、現在も有効な状態にある。

That patent is still in a valid state currently.

'Tokkyo' (patent) is a formal legal noun.

1

有効な意思表示がなされたかどうかが争点となった。

Whether a valid declaration of intent was made became the point of contention.

'Ishi hyōji' (declaration of intent) is a legal term.

2

有効な資源の再分配は、国家の存立に関わる問題だ。

The effective redistribution of resources is a matter related to the survival of the nation.

'Saidai-bun' (redistribution) and 'sonritsu' (survival).

3

有効な反論を封じ込めるための狡猾な戦略だ。

It is a cunning strategy to suppress effective counterarguments.

'Hanron' (counterargument) and 'fūjikomeru' (suppress).

4

有効な条約締結に向けて、長年の交渉が続けられた。

Years of negotiations were continued toward the conclusion of a valid treaty.

'Jōyaku teiketsu' (conclusion of a treaty).

5

この哲学的な問いに対する有効な答えは見当たらない。

No valid answer to this philosophical question can be found.

'Miataranai' (cannot be found/is not seen).

6

有効な市場原理が働かない場合、政府の介入が必要となる。

When effective market principles do not work, government intervention becomes necessary.

'Shijō genri' (market principles) and 'kanyū' (intervention).

7

有効な著作権の保護期間が終了し、公有財産となった。

The valid copyright protection period ended, and it became public domain.

'Chosakuken' (copyright) and 'kōyū zaisan' (public domain).

8

有効な教育的配慮が、子供たちの将来を左右する。

Effective educational consideration influences the children's future.

'Sayū suru' (to influence/decide).

常见搭配

有効な手段
有効な期間
有効な活用
有効な対策
有効な方法
有効な書類
有効な意見
有効な一打
有効な証拠
有効な情報

常用短语

有効期限

— Expiration date or validity period. Found on almost all cards and food.

有効期限はいつですか?

有効活用

— Making effective use of something that might be wasted.

空き地の有効活用。

有効打

— An effective blow in sports like boxing or kendo.

有効打を当てる。

有効性

— The quality of being effective; efficacy.

ワクチンの有効性を確認する。

有効求人倍率

— The ratio of job offers to job seekers. A key economic stat.

有効求人倍率が下がった。

有効範囲

— The valid range or scope of something.

Wi-Fiの有効範囲。

有効数字

— Significant figures in mathematics and science.

有効数字は三桁です。

有効成分

— The active ingredient in medicine.

有効成分が含まれている。

有効投票

— A valid vote in an election.

有効投票数を数える。

有効期間

— The duration for which something is valid.

パスポートの有効期間。

容易混淆的词

有効な vs 効果的 (Kōka-teki)

Kōka-teki is about the result/impact; Yūkō is about the validity/power.

有効な vs 効率的 (Kōritsu-teki)

Kōritsu-teki is about speed/efficiency; Yūkō is about whether it works/is valid.

有効な vs 有能 (Yū-nō)

Yū-nō is for talented people; Yūkō is for methods/documents.

习语与表达

"有効に使う"

— To use something (usually time or money) without wasting it.

時間を有効に使おう。

Neutral
"有効な手を打つ"

— To take a strategic and effective action to solve a problem.

早めに有効な手を打つべきだ。

Formal
"有効な一石"

— Metaphorically, an effective move (like a stone in the game of Go).

彼の一言は有効な一石だった。

Literary
"有効なカード"

— A 'trump card' or a valid option to use in a negotiation.

まだ有効なカードが残っている。

Informal
"有効な一撃"

— A decisive and effective blow.

有効な一撃を加える。

Neutral
"有効を期す"

— To aim for effectiveness or validity.

万全を期し、有効を期す。

Formal
"有効に働く"

— To work effectively or have a positive effect.

薬が有効に働いている。

Neutral
"有効な距離"

— The effective range (e.g., for a weapon or a tool).

有効な距離を保つ。

Technical
"有効な足跡"

— Leaving a valid or effective mark/legacy.

歴史に有効な足跡を残す。

Literary
"有効な対話"

— Productive and effective dialogue.

有効な対話を進める。

Formal

容易混淆

有効な vs 有効 (Yūkō)

Both translate to 'effective'.

Yūkō is 'valid/functional'; Kōka is 'result-producing'.

有効な薬 (Valid/working medicine) vs 効果的な薬 (Medicine that produced a great result).

有効な vs 効率 (Kōritsu)

Both relate to doing things well.

Kōritsu is about 'doing things fast/cheaply'.

効率的な作業 (Efficient work).

有効な vs 有用 (Yūyō)

Both mean 'useful'.

Yūyō is more about 'utility' or 'being of use'.

有用な人材 (Useful person).

有効な vs 有力 (Yūryoku)

Sounds similar.

Yūryoku means 'powerful' or 'influential'.

有力な候補 (A strong candidate).

有効な vs 有益 (Yūeki)

Both mean 'beneficial'.

Yūeki is about 'profit' or 'benefit' to one's mind/wallet.

有益な本 (A beneficial book).

句型

A1

[Noun] は有効です。

このチケットは有効です。

A2

有効な [Noun] を持っています。

有効なカードを持っています。

B1

[Noun] を有効に [Verb]。

時間を有効に使います。

B1

有効な [Noun] が必要です。

有効な対策が必要です。

B2

[Noun] の有効性は [Adjective] です。

この薬の有効性は高いです。

B2

有効な期間内に [Verb]。

有効な期間内に申請してください。

C1

[Noun] が有効であると見なされる。

証拠が有効であると見なされる。

C2

有効な意思表示に基づき [Verb]。

有効な意思表示に基づき契約する。

词族

名词

有効 (Validity/Effectiveness)
有効性 (Efficacy)
有効期限 (Expiration Date)

动词

有効にする (To enable/make valid)
有効活用する (To utilize effectively)

形容词

有効な (Valid/Effective)

相关

効く (To be effective/work)
効果 (Effect)
効率 (Efficiency)
効力 (Legal force)
効用 (Utility)

如何使用

frequency

Very high in business, legal, and daily bureaucracy.

常见错误
  • Using 'yūkō' for a talented person. Use 'yū-nō' (有能).

    'Yūkō' is for validity/effectiveness of things. 'Yū-nō' is for the capability of people.

  • Saying 'yūkō hōhō' without 'na'. Say 'yūkō na hōhō'.

    'Yūkō' is a na-adjective and requires 'na' to modify a noun.

  • Confusing 'yūkō' with 'kōritsu' (efficiency). Use 'yūkō' for 'working/valid' and 'kōritsu' for 'fast/cheap'.

    Something can be effective (yūkō) but not efficient (kōritsu) if it takes too much energy.

  • Pronouncing it as 'yuko' (short vowels). Pronounce it as 'yūkō' (long vowels).

    'Yuko' is a name; 'yūkō' is the adjective. The long vowels are crucial for meaning.

  • Using 'yūkō' to mean 'pretty' or 'good' in a general sense. Use 'ii' or 'kirei'.

    'Yūkō' is specific to functionality and legal validity.

小贴士

The 'Na' Rule

Never forget the 'na' when 'yūkō' comes before a noun. It's 'yūkō na hōhō,' not 'yūkō hōhō.'

Time Management

In a Japanese interview, saying you like to use time 'yūkō ni' (effectively) is a great way to show you are organized.

Check Your Passport

If you see the word '有効期限' (yūkō kigen) on a Japanese form, it's asking for your passport or ID's expiration date.

Contract Validity

When signing a contract, the word '有効' determines when the agreement starts and ends. Always check the 'yūkō kikan.'

The 'U' and 'O'

Both vowels are long. Think of 'Yuu' and 'Koo'. Skipping the long vowels might make it sound like a different word.

Coupons

Check the bottom of Japanese receipts. If you see '有効,' it means there is a valid discount code there!

Active Ingredients

On medicine boxes, '有効成分' (yūkō seibun) lists what actually makes the medicine work.

Scoring

In Judo, a 'Yuko' was a score. Even if the rules change, the word still implies a 'valid' effort.

Kanji Practice

Practice the '効' kanji. It's used in many important words like 'kōka' (effect) and 'kōritsu' (efficiency).

Agreeing

If someone makes a very logical point, you can say 'Sore wa yūkō na iken desu ne' to show you find their opinion strategically sound.

记住它

记忆技巧

'You go' (Yū-kō) if your passport is valid! If you want to 'go' to Japan, your documents must be 'yūkō'.

视觉联想

Imagine a green checkmark (✅) on a passport. The checkmark represents the 'effect' (kō) that the document 'has' (yū).

Word Web

Passport Ticket Strategy Time Medicine Contract Visa Coupon

挑战

Try to find three things in your wallet right now that are 'yūkō' and one thing that is 'mukō' (like an old receipt).

词源

Derived from Middle Chinese roots. 'Yū' (有) means 'to have' and 'Kō' (効) means 'result/effect.'

原始含义: Possessing a result or merit.

Sino-Japanese (Kango).

文化背景

No specific sensitivities, but ensure 'yūkō' is not used to describe a person's worth, only their skills (use 'yūno' for that).

English speakers often use 'valid' for documents and 'effective' for results. Japanese uses 'yūkō' for both, which can be confusing at first.

Judo scoring (Yuko) Japanese Civil Code (Minpō) articles on validity. Economic reports on 'Yūkō Kyūjin Bairitsu'.

在生活中练习

真实语境

At the Airport

  • 有効なビザ (Valid visa)
  • 有効なパスポート (Valid passport)
  • 有効期限の確認 (Checking expiration)
  • 有効な書類 (Valid documents)

Business Meeting

  • 有効な対策 (Effective measures)
  • 時間を有効に使う (Use time effectively)
  • 有効な投資 (Effective investment)
  • 有効な提案 (Effective proposal)

Shopping

  • 有効なクーポン (Valid coupon)
  • 有効なカード (Valid card)
  • 有効期限が切れている (Expired)
  • 有効なレシート (Valid receipt)

Medical/Health

  • 有効な薬 (Effective medicine)
  • 有効成分 (Active ingredient)
  • 有効性を試す (Test efficacy)
  • 有効な治療 (Effective treatment)

Legal/Contracts

  • 有効な契約 (Valid contract)
  • 有効な意思表示 (Valid intent)
  • 有効な期間 (Valid period)
  • 有効性を争う (Dispute validity)

对话开场白

"時間を有効に使うために、何か工夫していますか? (Do you do anything special to use your time effectively?)"

"日本で有効な運転免許証を持っていますか? (Do you have a driver's license that is valid in Japan?)"

"このクーポンはまだ有効だと思いますか? (Do you think this coupon is still valid?)"

"最近、仕事で有効な対策を見つけましたか? (Have you found any effective measures at work recently?)"

"一番有効な日本語の勉強方法は何だと思いますか? (What do you think is the most effective way to study Japanese?)"

日记主题

今日は時間を有効に使えましたか?何をしたか書いてください。 (Did you use your time effectively today? Write about what you did.)

あなたが持っている有効な資格について説明してください。 (Explain the valid qualifications/licenses you have.)

有効なストレス解消法は何ですか? (What is an effective way for you to relieve stress?)

もし魔法の有効期限が一日だけなら、何をしますか? (If a magic spell's validity was only for one day, what would you do?)

社会にとって有効なルールとは何だと思いますか? (What do you think constitutes an effective rule for society?)

常见问题

10 个问题

Generally, no. 'Yūkō' is for methods, documents, or actions. To say a person is effective or talented, use 'yū-nō' (有能な).

'Yūkō' means something is valid or has the power to work (like a valid passport). 'Kōka-teki' means something produced a visible effect (like an effective ad).

The most common term is 'yūkō kigen' (有効期限). You see this on credit cards and food.

It is neutral to formal. It is used in daily life for tickets but also in very formal legal documents.

Not exactly. 'Efficient' is 'kōritsu-teki.' However, 'yūkō ni tsukau' (use effectively) often implies not wasting time, which is similar to efficiency.

Yes, especially in martial arts like Judo, it refers to a valid point or an effective move.

The opposite is 'mukō' (無効), meaning invalid or void.

It sounds strange. Use 'yū-nō na hito' for a talented person or 'tayori ni naru hito' for a reliable person.

Yes. 'Yūkō-sei' refers to the efficacy of a drug, and 'yūkō-seibun' refers to the active ingredient.

Add 'ni' to make 'yūkō ni.' Example: 'Jikan o yūkō ni katsuyō suru' (Utilize time effectively).

自我测试 200 个问题

writing

Translate: 'This passport is valid.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'Let's use time effectively.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'Please tell me an effective method.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'The contract is valid for one year.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'We need an effective measure.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'Check the expiration date.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'This medicine is effective for headaches.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'It is a valid document.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'He has a valid visa.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'Use resources effectively.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'The system is functioning effectively.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'There is no valid evidence.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'The efficacy of the vaccine was confirmed.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'Is this coupon still valid?'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'I am looking for an effective way to study.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'The valid range is 10 meters.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'Make the most of your vacation.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'It was a valid point.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'The copyright is still valid.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
writing

Translate: 'Provide a valid ID.'

Well written! Good try! Check the sample answer below.

正确! 不太对。 正确答案:
speaking

Say 'Is this ticket valid?' in Japanese.

Read this aloud:

正确! 不太对。 正确答案:
speaking

Tell a friend: 'Let's use our time effectively.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Explain that your passport is valid until next year.

Read this aloud:

正确! 不太对。 正确答案:
speaking

Ask a staff member: 'Until when is this coupon valid?'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Suggest taking 'effective measures' in a meeting.

Read this aloud:

正确! 不太对。 正确答案:
speaking

State that 'This medicine is effective for a cold.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Tell someone to utilize the resources effectively.

Read this aloud:

正确! 不太对。 正确答案:
speaking

Ask: 'Do you have a valid ID?'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Say: 'The system is working effectively.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Say: 'That was a valid opinion.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Explain that the expiration date has passed.

Read this aloud:

正确! 不太对。 正确答案:
speaking

Describe a 'valid reason' in Japanese.

Read this aloud:

正确! 不太对。 正确答案:
speaking

Say: 'The efficacy of the vaccine is high.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Say: 'This is a valid contract.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Ask: 'Is there an effective method?'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Say: 'The valid range is limited.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Say: 'Please use the space effectively.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Say: 'That's an effective blow.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Say: 'The data is valid.'

Read this aloud:

正确! 不太对。 正确答案:
speaking

Say: 'I want to have a valid discussion.'

Read this aloud:

正确! 不太对。 正确答案:
listening

Listen to the phrase: '有効な対策'. What does it mean?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効期限は明日です'. When is the expiration?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '時間を有効に使いましょう'. What is the speaker suggesting?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: 'このカードは有効ですか?'. What are they asking?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効な方法が必要です'. What is needed?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効性は確認されました'. What was confirmed?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効な書類を提出してください'. What should be submitted?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効打がありました'. What happened in the sport?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効な身分証明書'. What is this?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効期間は3年です'. How long is the valid period?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効に機能しています'. How is it working?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効活用しましょう'. What should we do?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効な意見です'. What kind of opinion is it?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効な範囲内です'. Is it inside or outside the range?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:
listening

Listen to: '有効な一石を投じる'. What does this idiom imply?

正确! 不太对。 正确答案:
正确! 不太对。 正确答案:

/ 200 correct

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