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The very expensive ones are made of tamahagane steel. Producing steel from iron sand is very labour-intensive.

https://en.wikipedia.org/wiki/Tamahagane

I never owned a tamahagane razor so...

Are you going to explore a new rabbit hole?
I have a Tosuke and an Iwasaki.
Crazy sharp razors. I don't use them enough I am afraid.
You have to be very careful not to damage the cutting edge.