Book Summary in Japan
Japan — Books, for consumers. Niche: Book Summary App.
Data from the week of 19 Oct 2026, refreshed every two weeks.
Our call
this week
Score 45/100 · why few pass 70
We have not checked this against App Store search in Japan yet, so we won’t call it. Checks run every day, highest-scoring openings first.
At a glance
- Demand
- Medium, neither for nor against you
- 3,091 ratings here · 10,644 in the US and UK
- Revenue
- Low, against you
- No chart revenue
- Competition
- Low, in your favour
- 2 established in Japan
- Leading apps
- Fair, neither for nor against you
- 4.2★ average
How the score of 45 is made
score out of 100
- Demand68
10,644 ratings in the US and UK, 3,091 in Japan
- Revenue0
0 of the top 2 on a top-grossing chart in the last 30 days; 0 paid
- Room locally76
2 established apps in Japan (75+ ratings, scaled to the market’s size)
- Language gap44
Not checked in local search yet — counted as neutral (50) at most
- Incumbent weakness45
4.2 stars on average in Japan; 1 of 2 not updated in a year
- AI gap30
2 of the top 2 not built around AI
- Momentum—
History building since 26 Oct 2026 — counted as neutral (50) for now
Why this is an opening
Among the top 2 apps in Japan, 1 is stale, making up 50% of the leaders. Both of these top apps are non-native, leaving space for a focused modern product. Local readers have generated 3091 ratings for these top offerings despite the lack of recent updates.
What people in Japan see
Not yet checked against local App Store search. Checks run every day, highest-scoring openings first.
How strong the competition is
The leading apps in this niche
The niche’s apps available in Japan, ranked by their share of ratings here and in the United States and United Kingdom; stars in Japan where it has them.
| App | Ratings in Japan | Ratings US + UK | Stars | Japanese | Last update | AI |
|---|---|---|---|---|---|---|
| 本の要約 フライヤー/ビジネス書・読書 本の要約アプリ | 2,875 | 0 | 4.1 | Yes | Oct 2026 | No AI |
| Instaread: Learn Something New | 216 | 10,644 | 4.5 | No | Jun 2025 | No AI |
MembersSee all competitors, complaint themes and history.
What users complain about
Too few low-star reviews to group into complaints yet.
If you build it
The smallest app that answers what users complain about and what the leaders leave out. Each feature says where it comes from.
- App Store keywords in Japanesethe terms searched and which app tops eachMembers
- What apps here chargethe leading apps' in-app prices, once we have read themMembers
What would kill this
MembersUp to three things that would end this opening, each tied to the data.
The same niche in other markets
- This market
- Other markets
✓ checked against local App Store search. Other markets are named for members.
Show as a table
| Market | Score | Checked against local search |
|---|---|---|
| Japan | 45 | Not yet |
| Members | 45 | Not yet |
| Members | 42 | Not yet |
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Every competitor, complaint and market, and the build plan, for every opening.
Get 30 days — €19or €9/monthScored 2026-10-27 with score version 5. How the score works. Store data only: we do not estimate revenue or downloads.