The problem At a real mahjong table, there's a specific pause that happens when you're holding a tile you can't commit to throwing. The discard wall has information — what's been pushed out early, what's been held back — but reading it quickly under pressure is genuinely hard. OkkanaiPai is the tool Niixo Labs built for that pause. It doesn't teach mahjong or explain theory. It just shows which tiles are dangerous right now, given the discards already visible on the table. How the interaction works Tap in the discards you can see, swipe between the four seats, and the app color-codes all 34 tiles by danger level in real time. The design is meant to fit the table: fast input, glanceable output, no account, no network. The calibration data The underlying stats come from 4.97M discards across 16 days of Tenhou's Houou-takujo — the top-rated tables on Japan's largest online mahjong platform. We calibrated against those logs and landed at AUC 0.83.…