blunt katana

[jezah81]

What would be the best way to find out if your katana is getting blunt? Is there any experiments to do?
I first bought my sword lasy year in April and have cut with it about 20 times since then. A few cuts on bamboo but mainly on beach bats recently. So as you can see i havent cut many times. When i first bought it i could cut paper but now it doesnt cleanly slice through the paper like it used to? Is this normal? Does this happen to every katana only after a few cuts?
Regards,

[socho]

Have to assume you are talking about a production blade, a Chen or Cold Steel or something else from China. Some of these are made with 'softer' steel or are not differentially tempered, so may not hold an edge very well and would require regular maintenance (sharpening). If it does not cut paper or just does not cut as well as it did, and your technique is not to blame, then ...
Not usually a problem with nihonto, or even gunto. And should not be a problem with something of reasonably good steel, properly shaped and differentially tempered. We have a remounted gunto era blade (Mantetsu) that we use as a dojo 'cutter'. Was sharpened once, three or four years ago. Hundreds of cuts later, still a laser, no problem.

Dave

[Brian Owens]

Another thought; if the blade was not properly sharpened when you got it -- with insufficient niku (in a worst-case scenario even being hollow-ground) -- it could cut paper very well, then -- when exposed to harder materials like bamboo -- a thin, almost microscopic, strip along the edge could actually "fold over" rendering it unable to cleanly cut paper but still able to cut wara.

Old timers who remember "stropping" a straight razor after sharpening will know what I'm referring to.

As a watchmaker, after sharpening my gravers I always have to "unsharpen" them slightly by drawing the edges along a stone to remove the "wire edge" to keep them from almost instantly dulling the first time I try to cut with them.

I think this may be what is happening with your blade. The best thing to do would be to have a qualified token look at it to see if it should be repolished.

If you tell him that you want a good cutting polish, and not a show polish, it wouldn't be as expensive a job.

HTH.

[jezah81]

Thanks guys.
It has no effect on the beach mats. It cuts them very well. I guess ill just wait until it really gets blunt then get it polished.
Regards,

[Brian Owens]

Another thing I'm just remembering something related to this: I saw a movie once (can't remember where, when, or what) where the main character was preparing for an upcoming battle or duel. He was holding his sword in one hand and running a stone lengthwise down the blade with the other.

I imagine any sword collectors or sword polishers in the audience were horrified by the cavalier way he was doing this, but I just smiled. He wasn't getting ready to enter the blade in a show, he was getting ready to kill or be killed.

A couple of light strokes on each side of the ha might be all that you need to restore your edge to full sharpness. But if you're not comfortable doing that, or if it's a valuable blade, then I'd err on the side of caution if I were you.

HTH.

[chrismoses]

Brian, that's exaxtly how most of my Sempai in Japan treat their practice swords. One of them is even a token. They just run to the back of the dojo during tameshigiri and scrape a ceramic stone down the blade a few times. When we told them that we didn't even do that with our Chinese blades, their comments were that we must have awfully dull blades and gave us a "touch-up" ceramic stone for our dojo as a parting gift. Sine then, I've had no trouble scraping my Bugei/ Chen wares on occasion.

[jezah81]

Thanks again.
What is this "ceramic" stone you are talking about? Is it the grey stones you can buy to sharpen knives?
Regards,

[Brian Owens]

Originally posted by jezah81
What is this "ceramic" stone you are talking about? Is it the grey stones you can buy to sharpen knives?
Since I'm not trying to re-shape a blade, nor remove much metal, I use a very fine grit stone. The one I use is quarried here in the USA, and is an almost white stone called a "hard Arkansas stone."

Arkansas stones come in many sizes, in very fine and fine grits, and in both natural and synthetic varieties.

Chris, can you post a picture or describe in more detail the stone you were given in Japan? I'd like to know what the "real deal" looks like, and maybe see if they're available to order someplace.

[chrismoses]

If you go to this page (http://www.fine-tools.com/japwas.htm), about 1/2 way down there is a stone mounted on a plastic stand. The stone they gave us looks like one of these cut in 1/2 (so making it more like a square), but it is mounted on a wooden stand. I'm not sure what grit it is, but it's pretty smooth. Just from the way if feels relative to sandpaper I would guess in the 1000-2000 range. It's a light yellow color, like custard. Hope this helps.