For app developers and marketers aiming for global expansion, how are you approaching your app localization?
If you think, “We translated the store text into the local language and swapped the text on the screenshots, so we’re done!”—you might be missing out on huge opportunities. What truly matters in ASO localization is not mere “language translation,” but “store page optimization” tailored to the user behavior and culture of each market.
In this article, based on the ranking data of the iOS App Store “Productivity” category as of August 2026, we compared Japan and Korea ASO. We will share the insights of both countries, drawn from the apps ranked in both markets and the apps unique to each market’s ranking.
Contents
1. The “Wall of Localization” Seen from Popular Apps Common to Japan and Korea
As of August 13th, out of the top 25 productivity apps in Japan and Korea, 12 apps were common to both (e.g., ChatGPT, Gmail, Google Drive, Notion).
| Titles that overlap in the iOS Top 25 (as of August 13, 2026) | ||
| JP | KR | |
| 1 | ChatGPT | Google Gemini |
| 2 | Google Gemini | Claude by Anthropic |
| 3 | Gmail – Google のメール | K-패스 |
| 4 | Claude by Anthropic | ChatGPT |
| 5 | Google ドライブ – 安全なオンライン ストレージ | TeraBox: 1TB 클라우드 저장소 & AI 공간 |
| 6 | Grok 生成AI | Gmail: Google이 제공하는 이메일 |
| 7 | Yahoo!メール | Google Sheets |
| 8 | Google スプレッドシート | Google 드라이브 – 안전한 온라인 파일 저장공간 |
| 9 | TimeTree タイムツリー – カレンダーや予定表の共有 | Grok AI |
| 10 | Google ドキュメント | Mirosoft Authenticator |
| 11 | Mirosoft Authenticator | 클로바노트 – 음성 그 이상의 기록 |
| 12 | Microsoft Excel | Notion: 메모, 작업, AI |
| 13 | Google カレンダー | 네이버 메일 |
| 14 | シフトボード：バイトの給料計算とシフト管理 | 에이닷 – 나만의 AI 개인비서 |
| 15 | Windows にリンク | VPN – Super Unlimited Proxy |
| 16 | Microsoft Outlook | Google Docs |
| 17 | Googleバンドル | vFlat Scan – PDF 스캐너 |
| 18 | Microsoft Word | AnySchedule – 올인원 캘린더 & 플래너AnySchedule – 올인원 캘린더 & 플래너 |
| 19 | Microsoft Copilot | CJ대한통운 오네 |
| 20 | Yondo Todoリストをロック画面に。シンプルタスク管理 | Google 캘린더: 일정을 정리하세요 |
| 21 | Taska: やることリスト&プランナー | 국군복지포털 |
| 22 | シンプルカレンダー – スケジュール帳、予定表かれんだー管理 | TimeTree 캘린더 공유 앱 |
| 23 | Colorkrew Biz | minical – 일정 관리 캘린더 앱 (달력) |
| 24 | Microsoft OneDrive | Windows와 연결 |
| 25 | Notion：メモ、タスク、AI | 삼성화재 다이렉트 자동차보험 |
Comparing these common apps reveals subtle nuance differences for each market that go beyond the language barrier.
The Pitfalls of Keyword Selection
Take email apps, for example. When checking search volumes with ASO tools, the keyword “メール (Mail)” has an overwhelmingly high usage rate in Japan, whereas in Korea, “이메일 (E-Mail)” is more commonly used.
Also, regarding Google apps, it’s common in Japan to use Katakana transliterations like “スプレッドシート (Spreadsheet)” and “ドキュメント (Document)”. However, in Korea, perhaps due to a higher familiarity with English words, the English terms “Google Sheets” and “Google Docs” tend to be used as is.
If you set keywords by direct translation, you must be careful, as you might miss out on high-volume keywords that local users actually search for.
Differences in Appeal Points (The Case of TimeTree)
The shared calendar app “TimeTree,” originating from Japan, is popular in both countries, but the nuances of its appeal differ.
- Japan: Calendar / Schedule / Family / Couples / Share
- Korea: Calendar / Family / Team / Scheduler
While the Japanese market primarily pushes the benefit of “being able to share with someone,” the Korean market strongly appeals to “efficiency in schedule management” using the word “scheduler” (スケジューラー), which is not commonly used in Japan. This is an excellent example of optimization tailored to cultural usage backgrounds.
The Reality of App Store Screenshots for Major Apps
Actually, many mega-apps like Gemini and Google Drive often use their English screenshots as they are, or simply translate the text mechanically without changing the design.
You might think, “Well, if the big players aren’t optimizing, maybe we don’t have to either.” However, they have already acquired overwhelming “brand awareness (navigational searches).” For apps that do not yet have high brand recognition to compete in overseas markets, it is essential to avoid mimicking the strategies of the giants. Instead, a gritty ASO strategy—meticulously optimizing App Store screenshots and text to catch the user’s eye—is absolutely necessary.
2. Japan’s Unique Trend: Peace of Mind and Trust Through “Numbers”
Next, let’s look at the trends of apps that rank high only in the Japanese market (e.g., Yahoo! Mail, Shiftboard, and various ToDo apps).
A major characteristic of ASO in the Japanese market is the “cultivation of peace of mind through track records (data).”
- Shiftboard: Prominently advertises “Total Downloads: 12 Million.”
- Simple Calendar: Places numerical information conveying reliability, such as “20 Million DL,” “No. 1 in Calendar Search,” and “8th Anniversary,” on the first or second screenshot.
When installing a new app, Japanese users tend to strongly care whether “many people are using it” and if it is “trustworthy.” Therefore, presenting specific numbers, track records, and catchy strengths (like Yahoo! Mail’s “No account switching needed”) in screenshots or subtitles to provide peace of mind is highly effective design.
3. Korea’s Unique Trend: The “AI” Appeal and Strong “Local Infrastructure”
On the other hand, from the list of apps that rank high only in the Korean market (e.g., K-패스, 클로바노트, 에이닷), we extracted two very interesting insights unique to Korea.
① The Powerful Hook of the “AI” Keyword
Looking at the unique top apps in Korea, the word “AI” frequently appears in titles and subtitles, such as “에이닷 (A. My Own AI Personal Assistant),”TeraBox (AI Space),” and “vFlat Scan (High-Speed Scan with AI).”
Korean users have exceptionally high sensitivity and receptivity to the latest IT trends. Communicating straightforwardly “how AI can make your work faster and more efficient” serves as a powerful motive for downloads.
② The Overwhelming Strength of the “Local Ecosystem”
Apps closely tied to the country’s infrastructure and portals, such as “K-패스 (Transit),” “네이버 메일 (Naver Mail),” “CJ대한통운 (Major Delivery),” and “삼성화재 (Insurance),” dominate the “Productivity” category.
The Korean market has a very strong local ecosystem led by “Naver” and “Kakao,” often outperforming foreign services.
4. Conclusion: A Trigger to Review Your Store Page
What became clear from the Japan-Korea ranking comparison is the definitive fact that “Translation ≠ Localization.”
- Japanese Market: Prefers the values of peace of mind, track record (numbers), and sharing.
- Korean Market: Prefers efficiency, the latest technology (AI), all-in-one solutions, and practical benefits.
Even if the target audience is users seeking “productivity,” the values of “what makes them feel efficient” change across borders.
For marketers and localization managers currently deploying apps to both the Japanese and Korean markets, please take this opportunity to review the status of your store page optimization. By taking a step beyond mere translation and executing ASO localization based on local search trends and user psychology, your download numbers should improve dramatically.
*This comparison is based on the top 25 apps in the iOS “Productivity” category as of August 13, 2026.
