Open-source app trains perfect pitch in kids before the window shuts at age 6

BSharp is an open-source Android app built on the premise that absolute pitch can only be acquired in early childhood — the developmental window effectively closes around age 6. It implements Eguchi’s chord identification method, a research-backed approach documented in Psychology of Music, in which children learn to recognize piano chords not by note name but by associated colors. Kids hear a chord and tap the matching colored flag, starting with just two (red and yellow) and unlocking new ones only after hitting 100% accuracy on the current set, with at least two weeks between additions.

The recommended regimen is short and frequent: roughly five sessions a day of two to three minutes each, totaling 20–25 identifications. The app tracks per-chord accuracy and uses an adaptive weighting scheme to surface harder chords more often, and it supports multiple user profiles for households with more than one child. The chord curriculum runs through nine white-key chords before introducing five black-key chords coded with secondary colors like gray, tan, and sky blue.

The project is derived from Paul Ganssle’s open-source CIM Trainer and rebuilt as a distinct tool at his request, licensed under Apache 2.0. It’s a developer-oriented release rather than a polished consumer product: building it requires Node.js, an npm install and make build step, and deploying to a device means opening the Android project in Android Studio and running it on a device or emulator.