What it is
A large round DC connector, separate from the AC inlet, developed in Japan. A CHAdeMO car has two sockets: one for AC, one for DC.
Speed you will actually see
Typically 50 kW at public posts. Higher-power CHAdeMO exists but is rare outside Japan.
Who needs it
Nissan Leaf and e-NV200, Mitsubishi Outlander PHEV, older Kia Soul EV and a handful of others. If you drive one, the shrinking network is the reason to check before setting off rather than after.
What the number above does not say
The count comes from connector tags in OpenStreetMap. A charging point whose socket has never been tagged is not in it, so the real total is higher than the figure shown — we would rather undercount than claim a socket nobody recorded. Availability is a separate question again: a mapped CHAdeMO post is not a working one, which is why every pin carries the last time a driver confirmed it, and says so plainly when nobody has.
Using it on the road
Filter to CHAdeMO before a long trip, not on arrival — these posts are getting rarer, not commoner. Reading the map needs no account; confirming that a charger worked is one tap and stays anonymous.