The problem sitting in plain sight
There's braille on train handrails, elevator buttons, and pill boxes all over Japan. Most people walk past it every day without a second thought — not because they don't care, but because almost nobody can read braille.
TenjiScan is our attempt to close that gap. Point your iPhone camera at any Japanese braille, get plain text back. That's the whole pitch.
Why we went fully offline
The first architectural decision we locked in was: no server. Braille appears on medication packaging, medical devices, banking equipment — contexts where sending someone's photo to a remote endpoint feels like a bad trade. It's not worth the privacy exposure.
Since v4.0.0, all recognition runs through a custom two-signal pipeline built on Vision. No network required, no image leaves the device. The trade-off is that we own the accuracy ceiling entirely — no external model updates — which pushes us to get the on-device pipeline right rather than lean on infrastructure.
What it actually supports
The app handles JIS Japanese braille (the national standard, JIS T 0921) and UEB Grade 1 English braille. Grade 2 contracted English braille isn't supported yet — contracted braille compresses text using shorthand symbols, and it's a meaningful gap for English-speaking users who depend on it in practice. We know. It's on the list.
The honest limitation
Lighting and shooting angle matter. Braille bumps cast shadows that make recognition possible, which means flat, even light actually hurts accuracy. We added UI guidance to help users find better angles, but in poor lighting the recognition still struggles. This isn't buried in fine print — it's just physics.
What surprised us
The use case we didn't fully anticipate: sighted people who are simply curious. Someone picks up a pill box they've owned for years and finally reads the braille on it. The app makes a small part of the tactile world readable without requiring expertise, and accessibility users have told us the on-device guarantee matters more to them than raw recognition speed.
TenjiScan is free on the App Store, with a one-time purchase to remove ads.
https://apps.apple.com/jp/app/id6759526188
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