# KINRAKU — See microbes before formulas

> See microbes before formulas (iPhone/iPad app by Fuji Bit Inc..)

- Source: https://appshunter.io/ios/app/kinraku/id6764113422 (this page in markdown: same URL + `.md`)
- Developer: [Fuji Bit Inc.](https://appshunter.io/developer/1874205957)
- Category: Education
- Price: Free
- Age rating: 4+
- Requires: iOS 13.0 · 24 MB
- Languages: Japanese
- Released: 2026-04-28
- Data updated: 2026-06-12
- User reviews in markdown: https://appshunter.io/ios/app/kinraku/id6764113422/reviews.md

## What is KINRAKU?

KINRAKU is a visual-first educational app for microbiology, infection dynamics, and evolution.

The 13th installment in the SUUGAKU / BUTURAKU / DENRAKU / HARAKU / NETURAKU / SEIRAKU / KORAKU / RYORAKU / RYURAKU / KAKURAKU / KIKARAKU / KAGAKU series. This time the theme is "microbes, infection, and evolution." Twelve core topics from high-school to introductory-university biology, all delivered through beautiful simulations and hands-on interaction.

[12 Features]

- Microbe Atlas
17 species across Bacteria, Archaea, Eukarya, and Viruses. Tap any card for shape, size, habitat, and role.

- Cell Structure
Cross-sections of all three domains. Bacterial nucleoid, plasmids, and flagellum; archaeal S-layer and ether-linked membrane; eukaryotic nucleus, mitochondria, ER, and vacuole — all labeled.

- Cell Division
Binary fission, budding, and sporulation animated through one full cycle. Watch N(t) = N₀ · 2^(t/g) climb as you tune the generation time.

- Petri Dish
Tap to inoculate three different microbes. Adjust nutrient, temperature, and pH to see colony growth shift and species compete where they meet.

- Biofilm
Planktonic cells attach to a surface and secrete an EPS matrix to build a 3D community. Watch the four stages — attachment, microcolony, maturation, dispersal — plus quorum-sensing switching and the high drug resistance inside the matrix. Tune attachment and growth rates.

- Chemotaxis
Bacteria swim toward nutrients (attractants) and away from toxins (repellents) via run-and-tumble. Move the source with a tap or drag and watch the population climb the gradient and aggregate. Tune cell count, sensitivity, and swim speed.

- Fermentation
Switch between lactic acid bacteria, yeast, and koji mold. Watch the substrate fall and products (lactate / ethanol / CO₂ / enzymes) accumulate, with live pH readout.

- SIR Simulator
180 agents wander and infect each other. Real-time epidemic curve, live S/I/R/V counts, and the basic reproduction number R₀. Sliders for β, γ, mobility, and vaccination dramatically reshape outbreaks.

- World Map
Metapopulation SIR over 7 Japanese regions, coupled by travel. Press lockdown to halt cross-region transmission; apply vaccination and observe herd-immunity effects.

- Immune System
Macrophages follow chemotactic gradients, chase pathogens, and engulf them. Tilt the balance between immune count and pathogen growth and watch infection establish or clear.

- Resistance Evolution
Three sliders: antibiotic concentration, mutation rate, growth rate. Apply pressure and watch susceptible cells die while rare resistant mutants take over — the resistance histogram shifts right as evolution unfolds.

- Tree of Life
The full tree from LUCA to the three domains and major clades. Pinch to zoom across billions of years of evolution.

[Highlights]
- Formula reference sheet on every screen
- Live dynamics for SIR, logistic growth, and selection
- Japanese / English support
- Dark mode / Light mode
- Clean, intuitive UI
- Only a small banner ad at the bottom

[Recommended for]
- High-school biology and university microbiology / public-health students
- Anyone wanting to intuitively grasp epidemic models and antibiotic resistance
- Teachers looking for interactive teaching materials
- Anyone curious about how life evolved at the microscopic scale


## Version history (last 3 releases)

### 2.0 — 2026-06-05

- Added two new features: Biofilm and Chemotaxis (now 12 in total)
- Reorganized the home screen into categories (Basics & Structure / Growth & Culture / Infection & Defense)
- Tooltips added to control buttons

### 1.1 — 2026-04-29

We have fixed the bug.

### 1.0 — 2026-04-28

No release notes.

## More apps by Fuji Bit Inc.

- [SUUGAKU](https://appshunter.io/ios/app/suugaku/id6759102221)
- [BUTURAKU](https://appshunter.io/ios/app/buturaku/id6759213255)
- [PAKEDOU](https://appshunter.io/ios/app/pakedou/id6759820254)
- [OKURERUNA！](https://appshunter.io/ios/app/okureruna/id6759956971)
- [HARAKU](https://appshunter.io/ios/app/haraku/id6759958253)
- [KORAKU](https://appshunter.io/ios/app/koraku/id6760215571)

All apps by Fuji Bit Inc.: https://appshunter.io/developer/1874205957

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-12.*