The Japanese language has several words to say ‘improvement’. It can be hard to tell what the difference is between them and in what situations each should be used. Furthermore, some of the words themselves are similar, which makes it even more difficult to differentiate. Let’s look at two such pairs of words and examine the individual meanings of each.
改良 (kairyou) vs. 改善 (kaizen)
改良 (kairyou) and 改善 (kaizen) are easily confused. Their first kanji is the exact same and their second respective kanjis have similar meanings. Each means ‘improvement’, which in English is a broad term, but 改良 and 改善 have specific nuances and refer to different senses of improvement.
改良 (kairyou) and 改善 (kaizen) both mean improvement, but 改良 means a specific change made to the structure of something to make it better. The change itself is the improvement. Whereas 改善 means better overall results are achieved due to changes made to something. The results are the improvement.
改良 (kairyou)
改良 is a noun or participle which takes the auxiliary verb する (suru)). Meaning: An improvement made by making a concrete change to something, often to a tangible object such as a machine or consumer product, but could also be something intangible, such as a computer program or work procedure, to make it look or work better. In the case of 改良, the change itself is the improvement. Kanji breakdown: 改 – reformation, change, modify, mend, renew 良 – good, pleasing, skilled Example sentences: スマートフォンのデザインを改良し、より持ちやすくしました。 We improved the design of the smartphone to make it easier to hold. 来週には、改良版のアプリをリリースする予定です。 An improved version of the app will be released next week. 電池の改良で、電気自動車の一回の充電で走れる時間がずっと長くなった。 With improved batteries, electric cars' single charge run time is much longer.
改善 (kaizen)
改善 is a noun or participle which takes the auxiliary verb する (suru)). Meaning: Overall better results, a better condition, or a better state achieved due to changes made to something, which could be tangible or intangible. In the case of 改善, the improvement is the new results, condition, or state, not the changes themselves. Kanji breakdown: 改 – reformation, change, modify, mend, renew 善 – virtuous, good Example sentences: あの会社の顧客サービスは以前より良くなったが、まだ改善の余地がある。 That company's customer service is better than what it used to be, but they still have room for improvement. オフィスの配置を少し変えただけで、職場環境は大きく改善されました。 We made some changes to the layout of the office, and it greatly improved the work environment. より健康になるために、生活習慣を改善したい。 I want to improve my lifestyle in order to be more healthy.
Let’s contrast 改良 and 改善 for a deeper understanding. 改良 refers to a specific concrete improvement, whereas 改善 refers to an overall abstract improvement. 改善 is results brought about by 改良, which are changes. Said another way, an improvement (改良) is made so that improvement (改善) is achieved. Said yet another way, you make 改良 for the purpose of 改善.
上達 (joutatsu) vs. 向上 (koujou)
The next pair of easily confused words to say ‘improvement’ are 上達 (joutatsu) and 向上 (koujou). This pair again shares one kanji in common. In a dictionary, their equivalent English definitions will probably both include the words ‘improvement’, ‘advancement’, and ‘progress’. But despite their similarity, each one has a unique meaning and appropriate situations in which it can be used.
上達 (joutatsu) and 向上 (koujou) both mean improvement, but 上達 is a specific term that means improvement in a particular skill or ability. It refers to a person’s capacity to do something. 向上 is a broad term which means something as a whole improves in the sense that it moves towards a better state.
上達 (joutatsu)
上達 is a noun or participle which takes the auxiliary verb する (suru)). Meaning: Improvement in a particular skill or ability, usually gained through practice with the goal of getting better. Kanji breakdown: 上 – above, up 達 – accomplished, reach, attain Example sentences: この一年、あなたは本当に日本語が上達しましたね。 You have really improved your Japanese this past year. 私はゲーム会社に就職するために、コーディングを上達させたいと考えています。 I really want to improve my coding so I can get a job at a video game company. トーストマスターズに参加すれば、必ず人前で話すことが上達するよ。 If you attend Toast Masters, your public speaking is sure to improve.
向上 (koujou)
向上 is a noun or participle which takes the auxiliary verb する (suru)). Meaning: Improvement, advancement, or elevation of something as a whole towards a better state or a higher level. Kanji breakdown: 上 – above, up 向 – tend toward, approach Example sentences: 大気の質は着実に向上している。 Air quality is steadily improving. 息子のために家庭教師を雇ってから、成績が向上した。 My son's grades have improved since I hired a tutor for him. 新しい大統領が選ばれてから、その国の生活環境は本当に向上しました。 Since the new president was elected, the living conditions in that country really improved.
Let’s address an important subtlety between 上達 and 向上 using an example. You can say 日本語が上達した, but you can’t say 日本語が向上した. If you say the latter, it means the Japanese language itself has somehow evolved into an improved form.
However, if you swap out 日本語 (Japanese language) and instead use the term 日本語力, which is Japanese language skill, then you can say either 日本語力が上達した or 日本語力が向上した. Perhaps we can think about it like this: 上達 is about improving a particular skill within us. When we do that, the skill within us improves. So, when we 上達 a skill, the skill within us 向上s.