I am new to collecting and I have question about a recent purchase. I purchased a late Edo Katana through Aoi-Art and it is currently in NBTHK Shinsa(Japan). I noticed in the pictures of the Katana that the rayskin under the Tuska has a line running down the middle. My fist impression is that it is a crack, however the line is perfectly straight going from top to bottom(including though the tang hole in the ray skin).
I have seen this line in the ray skin's on many of the older Katana's, so I have been second guessing the crack theory. I have referred to all of the books I can get my hands on, however I have hit a brick wall. Any thoughts?
Sorry, I would have provided a picture of the Tuska, however the picture did not meet the requirements for the post.
Thank you,
Jason