改修 in 30 Seconds
- Used for large-scale repairs of buildings, infrastructure, and software systems.
- Implies improvement and modernization, not just fixing a simple break.
- Commonly used in formal, business, and technical Japanese contexts.
- Distinguished from 'shūri' (small items) and 'kaizen' (process improvement).
The term 改修 (Kaishū) is a sophisticated Japanese noun and suru-verb that describes the process of repairing, renovating, or improving a physical structure or a technical system. Unlike simple repair terms like shūri, which might imply fixing a broken toaster or a torn shirt, kaishū carries a weight of structural integrity and modernization. It is the word of choice when an old bridge is reinforced to meet new earthquake standards, when a stadium is upgraded for an international event, or when a massive software database is overhauled to improve efficiency.
- Core Nuance
- Restoration with the intent of improvement or modernization.
- Physical Scope
- Buildings, dams, roads, ports, and large-scale facilities.
- Digital Scope
- System architecture, legacy codebases, and network infrastructures.
この古い図書館は来月から改修工事が始まります。(This old library will undergo renovation work starting next month.)
When you see kaishū, think of 'renewal.' It is not just about returning something to its original state, but often about making it better than it was before. This involves planning, engineering, and significant resources. In the context of Japanese urban development, kaishū is a constant presence, as the country balances the preservation of older structures with the necessity of modern safety requirements.
ダムの改修には多額の費用がかかる。(The renovation of the dam requires a large amount of money.)
システムの不具合を改修する。(To repair/improve a system bug.)
Using 改修 correctly requires understanding its formal and technical register. It is most commonly paired with suru to form a verb (改修する) or used as a prefix for nouns like kōji (construction) or hiyo (cost).
- Grammar Pattern 1
- [Object] + を + 改修する (To renovate/repair [Object])
- Grammar Pattern 2
- [Object] + の + 改修工事 (Renovation work of [Object])
In a business setting, you will hear this word during project meetings. If a client asks for a 'system kaishū,' they aren't just asking for a quick fix; they are likely asking for a structural change or a significant update to the logic of the program. In real estate, a kaishū project might involve adding insulation, replacing pipes, or reinforcing the foundation—tasks that go beyond mere cosmetic 'reforming' (リフォーム).
築50年のアパートを全面的に改修した。(We completely renovated the 50-year-old apartment.)
You will encounter 改修 in several specific environments. The most common is in public notices. If a train station entrance is closed, the sign will likely say '改修工事のため' (Due to renovation work). Similarly, in the news, when the government discusses infrastructure spending, kaishū is the standard term for maintaining national assets like highways and bridges.
- Public Announcements
- Parks, museums, and public toilets undergoing upgrades.
- IT Industry
- Patch notes, bug tracking systems (Jira/GitHub), and client requirements.
- Architecture/Real Estate
- Blueprints, contracts, and property listings.
駅のトイレが改修中で使えません。(The station toilets are under renovation and cannot be used.)
Furthermore, in the context of historical preservation, kaishū is used when a temple or shrine is being restored. This process is highly specialized, often called 'Heisei Kaishū' or 'Reiwa Kaishū' depending on the era in which the massive restoration project takes place.
The most frequent mistake learners make is using 改修 for small, personal items. You should not use kaishū for a broken smartphone screen, a leaky faucet in your kitchen (unless it's part of a larger building project), or a torn pair of jeans.
- Wrong Usage
- ❌ 靴を改修する (Renovate shoes) -> ⭕ 修理する / 直す
- Wrong Usage
- ❌ 宿題を改修する (Renovate homework) -> ⭕ 修正する / 直す
Another mistake is confusing kaishū with kaizen (改善). While both involve improvement, kaizen is about 'process' or 'quality' (making a habit better, improving efficiency), whereas kaishū is about the 'physical or systemic structure'. You kaizen your workflow, but you kaishū the office building.
Japanese has many words for 'fixing' or 'improving.' Understanding the boundaries of 改修 requires comparing it to its cousins.
- 修理 (Shūri)
- General repair of mechanical or electronic devices.
- 修繕 (Shūzen)
- Mending or minor repairs, often used for clothing or small household fixes.
- リフォーム (Rifōmu)
- Home renovation, often focused on aesthetics or interior layout.
- 補修 (Hoshū)
- Patching up or maintenance to prevent further damage.
壁のひびを補修する。(To patch up a crack in the wall.)
While kaishū is broad, hoshū is specific to maintenance. If you are adding a new wing to a hospital, it's kaishū. If you are just painting over a scratch on the hospital wall, it's hoshū.
How Formal Is It?
Difficulty Rating
Grammar to Know
〜に伴い (Along with)
〜にあたって (On the occasion of)
〜によって (By means of)
〜中 (Currently doing)
〜済み (Completed)
Examples by Level
駅は今、改修しています。
The station is being renovated now.
Verb form: 改修しています (is renovating).
古い公園を改修します。
We will renovate the old park.
Direct object: 公園を.
トイレの改修が終わりました。
The toilet renovation is finished.
Noun usage: 改修.
ここは改修工事中です。
This place is under renovation work.
Compound: 改修工事中.
来月、改修があります。
There is a renovation next month.
Simple existence: 改修があります.
学校を改修してください。
Please renovate the school.
Request: 〜てください.
このビルは改修が必要です。
This building needs renovation.
Necessity: 〜が必要です.
改修はいつですか？
When is the renovation?
Question: いつですか？
家を改修して、きれいにしました。
I renovated the house and made it beautiful.
Te-form for sequence: 改修して.
古いアパートを改修する予定です。
I plan to renovate an old apartment.
Plan: 〜予定です.
改修工事のため、道が通れません。
The road is closed due to renovation work.
Reason: 〜のため.
この図書館は去年、改修されました。
This library was renovated last year.
Passive voice: 改修されました.
キッチンの改修に一週間かかりました。
It took one week for the kitchen renovation.
Time duration: 一週間かかりました.
改修のおかげで、使いやすくなりました。
Thanks to the renovation, it became easier to use.
Benefit: 〜のおかげで.
市役所の改修について聞きました。
I heard about the city hall renovation.
Topic: 〜について.
改修費用はいくらですか？
How much is the renovation cost?
Cost: 改修費用.
システムのバグを改修しました。
I fixed the system bugs.
IT context: システムのバグ.
耐震改修を行う必要があります。
It is necessary to perform earthquake-resistance renovation.
Specific term: 耐震改修 (seismic retrofitting).
改修によって、建物の寿命が延びます。
The building's lifespan will be extended by the renovation.
Means/Cause: 〜によって.
予算が足りないので、改修を延期します。
Since the budget is insufficient, we will postpone the renovation.
Reason: 〜ので.
この施設は全面的に改修されるべきだ。
This facility should be completely renovated.
Opinion: 〜べきだ.
改修後のイメージ図を見せてください。
Please show me the image of the post-renovation design.
Time reference: 改修後.
プログラムのロジックを改修する。
To modify/improve the program logic.
Abstract structure: ロジックを改修.
改修工事のスケジュールを確認する。
Check the schedule of the renovation work.
Business task: 確認する.
老朽化したインフラの改修が急務となっている。
The renovation of aging infrastructure has become an urgent task.
Formal expression: 急務となっている.
大規模な改修プロジェクトが進行中だ。
A large-scale renovation project is underway.
Progress: 進行中.
改修にあたって、住民の意見を取り入れる。
In carrying out the renovation, we will incorporate the residents' opinions.
Formal 'when': 〜にあたって.
このシステムは大幅な改修が必要不可欠です。
Significant renovation is indispensable for this system.
Strong necessity: 必要不可欠.
改修工事に伴い、一部の施設が閉鎖されます。
In conjunction with the renovation work, some facilities will be closed.
Conjunction: 〜に伴い.
歴史的建造物の改修には細心の注意を払う。
Pay close attention to the renovation of historical buildings.
Collocation: 注意を払う.
改修によって、エネルギー効率が向上した。
Energy efficiency improved due to the renovation.
Result: 向上した.
既存の設備を最大限に活かして改修する。
Renovate by making the most of existing equipment.
Strategy: 〜を活かして.
都市再生計画の一環として、港湾施設の改修が決定した。
As part of the urban renewal plan, the renovation of port facilities was decided.
Context: 都市再生 (urban renewal).
改修費用を抑えるために、工法を工夫する。
Devise construction methods to keep renovation costs down.
Purpose: 〜ために.
長年の懸案だったダムの改修がついに着手された。
The renovation of the dam, which had been a long-standing issue, was finally started.
Nuance: 懸案 (long-standing issue).
改修工事の遅延が、プロジェクト全体の進捗に影響している。
The delay in renovation work is affecting the progress of the entire project.
Impact: 影響している.
システムの脆弱性を改修するためのパッチを適用する。
Apply a patch to repair system vulnerabilities.
Technical: 脆弱性 (vulnerability).
改修を繰り返すよりも、新築した方が安上がりな場合もある。
In some cases, it is cheaper to build anew than to repeat renovations.
Comparison: 〜よりも〜方が.
バリアフリー化を目的とした改修が進められている。
Renovations aimed at making facilities barrier-free are being promoted.
Goal: 〜を目的とした.
改修工事の騒音に対する苦情が寄せられている。
Complaints regarding the noise from the renovation work are being received.
Passive: 寄せられている.
老朽化した社会資本の計画的な改修は、国家の喫緊の課題である。
The planned renovation of aging social capital is a pressing national issue.
Academic: 社会資本 (social capital).
当該システムの抜本的な改修なくして、将来の拡張性は望めない。
Without a fundamental renovation of the system in question, future scalability cannot be expected.
Conditional: 〜なくして〜ない.
歴史的景観を損なうことなく、最新の設備を導入する改修手法が求められている。
Renovation methods that introduce the latest equipment without damaging the historical landscape are in demand.
Nuance: 〜を損なうことなく.
改修工事におけるアスベスト除去の安全基準が強化された。
Safety standards for asbestos removal in renovation work have been strengthened.
Specific: アスベスト除去.
建物の構造的欠陥を改修するには、高度な技術力を要する。
Repairing structural defects in a building requires advanced technical capabilities.
Formal: 〜を要する.
改修によって付加価値を高め、不動産投資の収益性を改善する。
Increase added value through renovation and improve the profitability of real estate investment.
Business: 付加価値 (added value).
デジタル・トランスフォーメーションの文脈において、レガシーシステムの改修は避けて通れない。
In the context of digital transformation, the renovation of legacy systems is unavoidable.
Idiom: 避けて通れない.
改修プロジェクトの成否は、ステークホルダー間の合意形成にかかっている。
The success or failure of the renovation project depends on the consensus building among stakeholders.
Nuance: 合意形成 (consensus building).
Common Collocations
Common Phrases
Often Confused With
Idioms & Expressions
Easily Confused
Sentence Patterns
How to Use It
Shuri is for broken things; Kaishū is for improving things.
Reform (リフォーム) is usually for home interiors; Kaishū is for structures and systems.
- Using it for small personal items (shoes, phones).
- Confusing it with 'kaishū' (回収 - collection).
- Using it for abstract improvements like 'improving your mood'.
- Forgetting the 'suru' when using it as a verb.
- Confusing it with 'kaizen' which is for processes, not objects.
Tips
Think Big
Always use kaishū for things that require a permit or a team of engineers.
Remember the Radical
The second kanji 修 has the 'person' radical on the left, implying human effort in repairing.
Pair with Kōji
Learning 'kaishū kōji' as a single block will help you recognize it in 90% of real-world cases.
Long Vowel
Don't forget the 'u' at the end. 'Kaishu' sounds like 'collection' (if short), but 'kaishū' is renovation.
Bug Fixes
If you work in tech, use 'bug no kaishū' to sound like a native professional.
Value Add
In property listings, 'kaishū-zumi' (renovated) is a major selling point.
Seismic Focus
In Japan, kaishū is often synonymous with safety upgrades.
Formal Reports
Use 'kaishū' instead of 'naosu' in any written business communication.
Station Signs
Look for the kanji 改修 when you see construction covers in public places.
Better than New
Remember that kaishū often implies the object is better after the work than it was originally.
Memorize It
Word Origin
Cultural Context
In Japanese IT companies, 'kaishū' is the standard term for modifying code, often preferred over 'shūri'.
Large-scale temple renovations are often public events where the community contributes.
Practice in Real Life
Real-World Contexts
Conversation Starters
"最近、近所の公園が改修されましたね。(The nearby park was renovated recently, wasn't it?)"
"家の改修を考えていますか？(Are you thinking about renovating your house?)"
"このシステムの改修にはどれくらい時間がかかりますか？(How long will the renovation of this system take?)"
"駅の改修工事、いつ終わるか知っていますか？(Do you know when the station renovation work will end?)"
"古い建物を改修してカフェにするのはどう思いますか？(What do you think about renovating an old building into a cafe?)"
Journal Prompts
もし自分の部屋を改修できるなら、どこを直したいですか？(If you could renovate your room, what would you want to fix?)
最近見た改修工事について書いてください。(Write about a renovation project you saw recently.)
日本の古い建物が改修されることの重要性について考えてください。(Think about the importance of renovating old Japanese buildings.)
仕事や勉強の『システム』を改修するとしたら、何をしますか？(If you were to 'renovate' your work or study system, what would you do?)
改修と新築、どちらが好きですか？その理由は？(Do you prefer renovation or new construction? Why?)
Frequently Asked Questions
10 questionsNo, for a watch you should use 'shūri' (修理). Kaishū is for larger things like buildings or systems.
Reform (リフォーム) is a loanword used mostly for home interior decoration. Kaishū is more formal and covers structural repairs and system upgrades.
Yes, it is very common in IT to mean fixing bugs or modifying system logic.
Generally, yes. It implies improvement or modernization, not just returning to a previous state.
It is 'earthquake-resistance renovation,' a very common term in Japan for making buildings safer against quakes.
You can say 'kaishū-chū' (改修中).
Yes, it is a kango (Chinese-origin word) and is considered formal and professional.
Usually 'shūri' is used for cars. Kaishū might be used for a major overhaul of a car's design or a fleet's system, but not for a simple fix.
There isn't a direct single word, but 'hakai' (destruction) or 'hōchi' (neglect) are conceptual opposites.
Yes, the kanji 修 is the same in both.
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Summary
Kaishū is your 'professional renovation' word. Use it for bridges, houses, and software codebases when you are making them better, safer, or more modern. It is a staple of news, construction, and IT industries.
- Used for large-scale repairs of buildings, infrastructure, and software systems.
- Implies improvement and modernization, not just fixing a simple break.
- Commonly used in formal, business, and technical Japanese contexts.
- Distinguished from 'shūri' (small items) and 'kaizen' (process improvement).
Think Big
Always use kaishū for things that require a permit or a team of engineers.
Remember the Radical
The second kanji 修 has the 'person' radical on the left, implying human effort in repairing.
Pair with Kōji
Learning 'kaishū kōji' as a single block will help you recognize it in 90% of real-world cases.
Long Vowel
Don't forget the 'u' at the end. 'Kaishu' sounds like 'collection' (if short), but 'kaishū' is renovation.
Example
家を改修します。
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