Couldn't make it past the 0:17, my mind had been too blown by learning that Japanese feudalism was born from sword manufacturing.

For someone like me who uses planes and chisels quite a bit, this was fascinating.

I actually had to watch this video during metallurgy class back when I was a welding apprentice.

The perfect blend of mild carbon on the inside, martinsite on the outside. The fact that they accomplished this with comparatively intuitive measures as compared to todays standards, its really impressive.

I wonder if you could do a poor-man's version of it by hard-casing mild carbon steel after you've fabricated the necessary pieces to make a sword-like thing.

I may eventually try this to see how well it works.

Incredible how they eyeball everything and go by feel, and yet centuries ago arrived at this highly complex and precise process. It really is art.

Much better than watching people make stuff up

Well of course those stones can cost up to thousands of dollars seeing as you're dumb enough to use rare large natural stones instead of synthetic stones which are much cheaper, have uniform particle size and density, and are otherwise superior in every way.