India's November 2016 move that instantly cancelled most of its paper money.
The engine sees it as an engineered shock that pushed the cash economy onto digital rails where it can be watched.
Wiping out 86% of currency forced informal cash dealings into trackable digital systems, followed by a new sales tax (GST) and Electoral Bonds, which channeled about $2.7 billion in anonymous corporate money to political parties until 2024.
It matters because it shows how a money change can quietly make a whole population more visible to those in charge.