Dan Scheid of Flying Horse Forge was kind enough to correct my description of
Japanese folded steel
. Pig Iron has too much carbon in it. The smiths working the metal were
removing carbon with a clean charcoal fire; rather than adding it.

This seems to imply that the hard, thin, center of the blade was made of
wrought iron and the better metal around it was the folded steel.

Dan mentioned other Damascus steel. I know of two types. The acid etched
Damascene steel looks good but is worthless except for display. Cable
Damascus, on the other hand is an extremely useful steel made from steel
wire. Dan Certo uses it to make Filet knives that can easily be bent into a
complete circle and snap back with no harm.