Alchemists, or goldsmiths?
Legend says Emperor Rudolf II's alchemists tried to make gold here. There's no evidence of that; the name more likely comes from goldsmiths who lived on the lane in the 17th century.
A row of doll-sized houses built into the castle's northern wall, home to guards, goldsmiths, a fortune teller and, for one winter, Franz Kafka. Here's what you're looking at, and what to listen for as you walk down it.

Legend says Emperor Rudolf II's alchemists tried to make gold here. There's no evidence of that; the name more likely comes from goldsmiths who lived on the lane in the 17th century.
His sister Ottla rented the small blue house at No. 22, and Franz used it to write in the evenings during the winter of 1916–1917, walking back down to the city at night.
At No. 14 lived Madame de Thebes, a fortune teller who predicted the fall of the Nazis. She died after being arrested by the Gestapo in 1943.
He wrote at No. 22, a house his sister rented, in the winter of 1916–1917.
Probably after the goldsmiths who lived there in the 17th century; the story of alchemists is a legend.
Yes, during the day it's part of the Prague Castle ticket circuits.