As someone new to Japanese knives it can be pretty overwhelming the different terms for things, e.g. hagane is iron/steel in Japanese, but has a more subtle meaning when it comes to knives. In trying to understand a description here I came across this and thought others might find it useful.
http://zknives.com/knives/kitchen/misc/jpnktknvterms.shtml
http://zknives.com/knives/kitchen/misc/jpnktknvterms.shtml