@inKraken @kathartes
Not sure what you're talking about. The only part of a blade that benefits from being hard is the edge, it's pointless for the rest of the blade to have hard steel. To combine a hard steel with a resilient steel you laminate it by forge-welding mild steel scales to a carbon steel core or a carbon steel edge to a mild steel core.
Folding modern steels is 100% aesthetic.
Also, I might have misinterpreted but there seems to be some minor confusion on the part of the katana. The katana was not folded in its entirety but rather laminated from pieces of folded steel. Minor point, I admit, but I felt it should be mentioned.