# iJishin vs J

The clearest difference is review sentiment: iJishin at 70% against J's 33%. iJishin also leads on update cadence (every 3 months vs every 13 months). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

iJishin ships an update every 3 months, J every 13 months. The most recent releases landed on October 21, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | iJishin | J |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[1.0 (1 ratings)](https://appshunter.io/ios/app/ijishin/id386745649/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | **70.0% of reviews** | 33.3% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 13 months |
| Monetization | Free | Free |
| Size | 21 MB | 9 MB |
| Requires iOS | 16.6 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Hakusan Corporation](https://appshunter.io/developer/386745652) | [National Research Institute for Earth Science and Disaster Prevention](https://appshunter.io/developer/427125457) |

## What reviewers say

### iJishin

[App page](https://appshunter.io/ios/app/ijishin/id386745649)

This application transforms your iPhone into a seismometer, allowing you to measure and analyze seismic vibrations. You can upload your observations to share with the public and utilize various tools for wave analysis, including graphical displays of power spectrum and displacement.

**Highlights:** Transforms iPhone into a seismometer, Measures seismic vibrations, Analyzes wave data, Uploads seismic observations, Graphical display of power spectrum, Measures velocity and displacement

**Features:** Vision Pro support

**In-app purchases:** none


### J

[App page](https://appshunter.io/ios/app/j-shis/id517160013)

This app provides official earthquake hazard maps for Japan, allowing users to view predictions of ground shaking intensity. It offers detailed information based on location and displays fault lines and seismic activity models.

**Highlights:** View national earthquake hazard maps, Zoom, pan, and adjust map transparency, Display probabilistic seismic hazard maps, Show surface and deep ground maps, View earthquake source fault locations, Display seismic activity models, Show location-specific earthquake probabilities

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is iJishin free?

iJishin is free to download, with no in-app purchases.

### Is J free?

J is free to download, with no in-app purchases.

### Do iJishin or J have ads?

Neither iJishin nor J shows ads.

### Which is updated more often, iJishin or J?

iJishin ships an update every 3 months, and J every 13 months. Most recently, iJishin was updated on October 21, 2026 and J on October 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*