What?!? Nankai makes a coaster-brake? Yes, and that was my reaction too. The coaster-brake is where their now infamous freecoaster was born. It has different (more complex) internals than their freecoaster version. When the hub was backpedaled, the clutch would engage with the spring nut, which would expand the brake shoes (the copper looking pieces) into the hub shell. It really was such a nice coaster brake. It’s spring mechanism is still used on the newer Nankai freecoaster.