Okey, this is my Japanese katana (that's a style sword, for those of you knot in the know) that I got recently. All I did was put the blade next to the camera and lower the colors so you could only see the blade. Hope you like!
Yeah that's what I first thought, that's the Hamon pattern, the clay slurry that's applied changed the rate at which the blade cools during its forgery, the speed at which the metal changes changes the qualities of the steel, and the strength, and, also, the colour.
Nice shot too, definitely something a little different than those usual Katana shots, although a little pixelated because of the editing.
Except on this one its a artificial hamon, usually just created by acid etching etc. A real hamon created by the forging process of combining steels of differing hardness and then tempering them in clays of differing thicknesses etc. is not going to creat the hamons 'wavy pattern' so identically and consistently.
Still fun to swing around outdoors... just don't hit anything harder than fruit. Nothing worse than having a piece of point steel crack and fly back at you.
One of the first 'katana' (just wallhangers made in Taiwan/China) had a fake hamon that was just perfect little triangles, not curves in the pattern at all, looked scary as it gave it a 'saw tooth' appearance.
I know this may be a late comment, but you should point out to Rags428 that the blade isn't serrated, but what he sees is the Hamon pattern, and that the cutting side is up. anyway, nice picture but a bit pixelated.
...first off. no 'katana' is serrated. what you have there is what we'd call a show blade. a sword-esque piece of sharp metal. besides, a traditional katana is curved to allow for more strength in the blade (as part of the cooling process). yours however, seems to be very straight from this angle.
(mine, would break yours in half)
in all fairness, it has an interesting and beautifully brutal appearance. and dont take my comment as hostile. i just like being able to apply what i know when i see an opportunity.