SJJIF vs Dirty Knife Timer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
SJJIF
Manage your sports event registrations and view fight schedules. Discover upcoming events happening near you. This official app is designed for members of the organization.
- Manage event registrations
- View fight schedules
- Discover upcoming events
- Official member app
- Event location discovery
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Official Free App for SJJIF Members. Manage your registration on events, see all your fights schedule and all the upcoming events nearby you.
Dirty Knife Timer
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This application is used to train quick-draw knife techniques, recording draw speed as a timer to enhance self-defense ability. We utilize the iPhone’s accelerometer to achieve this. Instructions: 1. Set your phone’s volume to maximum. 2. Set the countdown timer (can be a fixed time or random). 3. During the countdown, do not turn off the screen. Place the phone in your pocket. 4. When you hear the beep, immediately draw your knife. 5. The moment you come to a complete stop after drawing, the app will use accelerometer data to determine that you have finished the draw, thus calculating the time it took to draw the knife. Thank you to Matei Florin for inspiring me.
Screenshots
Verdict
The clearest difference is update cadence: Dirty Knife Timer at weekly against SJJIF's every 2 months. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
SJJIF ships an update every 2 months, Dirty Knife Timer weekly. The most recent releases landed on October 20, 2026 and October 25, 2026 respectively.
| Parameter | SJJIF | Dirty Knife Timer |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 2 months | Weekly — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 16.6 | 16.0 — better |
| Further details — not scored | ||
| Size | 28 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | Sports Jiu-Jitsu International Federation | Shun Man Leung |
In-app purchases
SJJIF
No in-app purchases
Dirty Knife Timer
No in-app purchases
