I think the term land in the context of chisels refers to the various ways the sides/edges are made? I thought I would make a post on this subject as it has been mentioned in several other posts but the actual definition was never qualified. The buzz around this term seems to revolve around how the sides of the chisel will work in corners and against the sides of dovetails.
It would seem obvious that trying to shove a square box into the more acute angle of a dovetail side would "bruise" the side's wall. I think this is why chisels come with quite a variety of land designs. The Japanese Shinogi chisel design, for instance, slopes both of the chisels sides to a single point at the top of the chisel, while the Kaku-uchi's sides are much closer to 90 degrees. The subject is somewhat more complicated than the single angle though as the bottom corners of chisels with sloped lands are sometimes rounded, chamfered, or the corner is ground off leaving a 90 degree edge.
The western world seems much more interested in dovetails than our friends in the eastern regions. I think all this talk about lands centers around having chisels with lands that can reach into the acute angles in dovetail sides without "bruising" the sides? Another question regarding lands has occurred to me though. The little experience I have with chisels suggests that the bottom corners of most chisels are the most fragile part. It seems to me, these corners would be more fragile than the rest of the cutting edge if the bottom corners are not 90 degrees. An angle of less than 90 degrees essentially creates more of a point, which would be easier to break off.
I would think, the bottom edge of a Japanese chisel would be even more susceptible to corner breakage due to the harder (more brittle) steel typically laminated to the bottom edge. As I understand the design of Japanese chisels the softer steel, used for the majority of the chisel body, serves as a shock absorber for the harder steel on the cutting edge. Therefore it would seem that a more acute bottom edge on a Japanese chisel would leave the harder steel exposed without softer steel above it to absorb shock.
I raise this question because it occurs to me that in our enthusiasm for chisels with acute bottom edges might we also be subjecting ourselves to chisels with inherently weak steel at the most fragile part of our chisels? Might Japanese chisel makers have a reason for making lands the way they typically do?