Sorobaco is not a math game. It is not a calculator trainer. No score, no levels, no explicit feedback. The system watches how you use the Soroban, your hesitations, errors, recovery time, rhythm and adjusts its pressure in response. Three phases gradually take you from full equation visible to pure mental operation, building toward Anzan: arithmetic without reference. The session ends when cognitive friction crosses a threshold. No announcement, no game over screen. The flow simply stops.

Framer — Launch websites with enterprise needs at startup speeds.

Launch websites with enterprise needs at startup speeds.

Hey Product Hunt! I built Sorobaco because I kept thinking about one question: can a digital tool teach a physical discipline without ever explaining it? The Soroban is a 17th-century Japanese abacus. Expert practitioners use it with their eyes closed. They don't calculate, they feel the number through their hands. Sorobaco tries to replicate that. Not by teaching. By watching. The app tracks your hesitations, errors, recovery time, and rhythm, then adjusts pressure in response. It doesn't tell you if you're good at math. It shows you what your mind does when it's under load. No score. No levels. No tutorials. The Soroban is the interface. Happy to answer questions, especially about the harder design choices, like why the session ends silently without any announcement. That one was genuinely difficult to commit to.