The following video is a fascinating lecture on the aesthetic qualities of the Japanese sword and its relationship to Japanese aesthetics more generally. It is astonishing the degree of detail and thought that went into the production of these weapons, as much symbolic and ceremonial as practical. As the video illustrates, the line of lighter hue along the edge of the blade is, in more developed periods, so distinctive as to be used to identify the particular smith and frequently contains visual motifs, such as the passing of clouds or the silhouette of a forest skyline.
There is, admittedly, something unnerving in the juxtaposition of violence and beauty in these swords, and yet one can only admire the craftsmanship of the smiths and the aesthetic genius they infused into their work.