Shiodoki is a specialized tide-charting utility for anglers in Japan, providing offline tide curves and moon data on iOS.
The App DNA
What makes this app unique?
The app removes the connectivity dependency of standard weather tools, serving users who need reliable data on remote shorelines or offshore where cellular signal is absent.
For Anglers and outdoor enthusiasts in Japan who require reliable, offline tide information for coastal and offshore activities.
What does it look like?
Key features
Computes tide data locally using bundled harmonic constants without network connectivity.
Unlocks multiple favorite ports, unlimited weekly look-ahead, notifications, and home screen widgets via a one-time purchase.
Uses device location to identify and calculate distance to the closest of 90 supported Japanese ports.
How much does it cost?
Freemium model using a one-time purchase to bypass subscription fatigue while gating advanced planning features.
Velocity
Maintenance developmentUX improvementsShow more...
The app maintains a maintenance-level cadence, with only one release recorded in the analyzed window. Development activity is currently limited to minor adjustments, as evidenced by the latest release addressing a display issue. There is no evidence of new features or live operations, indicating a focus on stability rather than growth. The app has been updated once in the last 8 days, reflecting a low-frequency update cycle.
Who built it?
Yuya Tanaka
3 apps tracked · Weather
ラダー図ノート - シーケンス制御の回路メモ
Quillbook: Check RegisterUser Sentiment
What do users think recently?
How are ratings & reviews evolving?
Not enough recent reviews to extract reliable themes yet.
Read the full review analysisCompetition
Competitive landscape for Shiodoki: Japan Tide Charts
How's the Weather market?
Shiodoki serves a specialized niche in the Japanese Weather category by focusing on offline utility for anglers. The one-time purchase model provides a clear alternative to the subscription-based pricing common in the broader weather app market.
Read the market outlookThe rivals identified
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Access the full report for freeThe Analyst's Read
Key takeaways for Shiodoki: Japan Tide Charts
Where is it heading?
The market for specialized coastal utility tools is consolidating around offline reliability, which benefits Shiodoki's current architecture. Maintaining this focus on utility over feature bloat will sustain its position, provided the development team addresses the lack of wearable integration to keep pace with angler needs.
- The offline-first mechanism provides a functional advantage that general-purpose weather apps struggle to match in remote coastal environments.
- The current maintenance-only cadence is sufficient for a utility tool but leaves the app vulnerable to competitors that might integrate wearable support.
The SWOT
- Offline-first architecture removes connectivity dependency
- One-time purchase model bypasses subscription fatigue
- Localized harmonic constants for 90 Japanese ports
- Expand port database beyond 90 locations
- Develop watchOS companion for active fishing
Next best moves
Ship watchOS companion app because anglers need hands-free tide data while fishing → increase daily active usage
The counter-intuitive read
The lack of network connectivity is not a…
Read the full takeSince the last report: The development roadmap shifted from a maintenance-only posture to an active investment in watchOS integration to solve mobile-handling friction for anglers. This pivot reorders the product strategy, prioritizing wearable utility over the previous focus on port database expansion.
Bottom line
Shiodoki secures a defensible niche by prioritizing offline reliability for the Japanese angling market, and the one-time purchase model creates a clear value proposition for users tired of subscription fatigue.
Unlock 2 critical frictions, 1 market threat and the analyst’s take.
Access the full report for freeFAQ
Does Shiodoki work without an internet connection?
How does Shiodoki's pricing compare to other weather apps?
Is Shiodoki suitable for professional navigation?
Are there alternatives for tide charts in Japan?
Sources
- [1] App Store listing, source
Report last updated