Evaluating shinai

[Anorymous]

Sorry if this has been posted before, but a quick search didn't come up with anything.

So, suppose you have a bamboo shinai in front of you, either used or new, and want to evaluate its durability without disassembling it. Let's assume we have zero knowledge about it before-hand; for all we know, we found it somewhere.

I've found that, among others, one should:

Look for "bruises" on the take (What are those caused by, anyway?)
Examine the yuuko-datotsu for dents/dimples
Evaluate each leather part by how dark its colour has become, how much it has frayed and how much it has stretched/given
Hold it at the handle and press the kensen against the floor, to see where and how easily it bends and
Look for cracks in the take

but I'm imagining there's much more that needs to be taken into account.

So? What other criteria are there to find out how much life a shinai has left?

[jjcruiser]

This is a very interesting question. But I think what I'd worry about is 5 (it's trash, throw it away or save just the good slats) and 4 (to reveal issues you can't see). The leather you can replace (I think half my shinai have fittings from other ones), the dents are normal from normal use and you should just rotate the slats, and I have no idea what you mean by bruises. Dark spots? Does that matter?

Just my two cents.

[verissimus]

6. Mold (especially on the inside of the slat)?
7. Dryness? Of course, this can be fixed by oiling, and I suspect is related to 4.

[Mr Yellow]

What about a bamboo knot within the yuuko-datotsu area? Do they affect the performance of the shinai?

[Anorymous]

[...] I have no idea what you mean by bruises. Dark spots? Does that matter?

By "bruises" I mean "black areas". They tend to be found more in cheaper shinai, so I assumed that they were indicative of low-class bamboo. I might of course be mistaken.


6. Mold (especially on the inside of the slat)?
7. Dryness? Of course, this can be fixed by oiling, and I suspect is related to 4.
Hm? I've never seen mould on any shinai, and haven't heard anyone warn against it either. How would it get moist enough to grow mould anyway?
You're right about the dryness, though. Indeed its elasticity would be a good measure, but there are other ones so I think it deserves separate mention.


What about a bamboo knot within the yuuko-datotsu area? Do they affect the performance of the shinai?
All bamboo shinai have a knot within the yuukou-datotsu. The average distance between knots is some 30cm, same as the length of it. Since having a knot near the kensen would make for a weird balance, the knot is positioned a little above the nakayui.

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To elaborate a bit, there were three separate cases wherein I thought this could be useful:
1) You go to a store and buy a shinai off the shelf, but aren't sure how good it actually is
2) Someone is offering you a used shinai, and you're trying to see how much use it has been through
3) You're trying to decide if a shinai of yours is better kept in use or retired.

Any advice that would be specific to some of those three use cases?

[DCPan]

This is an interesting topic.

1. Regarding bruises...if you see scratches and places where the surface is mildly scraped chipped, some folks have said that that is actually indicator of a more resilient shinai as it withstood the punishment of the elements before being harvested.

2. I prefer the first node to be about a "hand" span and a half from the tip, which would amount to roughly 26cm from the tip. Really though, you can take a part a carbon shinai and see where they placed it, as that's a good indicator of how the shinai will vibrate on impact. I think only the DB models have it though...the CF carbon shinai do not have inmitation nodes on the inside.

3. color is not a good indicator of tsuka because some are bleached while others aren't. I'd try to squeeze it to see how soft and dry it is instead.

Really though, it's hard to look for cracks until it's been taken apart.

Nowadays, I start with looking thru the batch to see how many have matching nodes first with the spacing I like and move on from there...really, after you oil it, the balance changes anyway.

[verissimus]

Hm? I've never seen mould on any shinai, and haven't heard anyone warn against it either. How would it get moist enough to grow mould anyway?

I once took apart a shinai for maintenance and saw this ugly brown deposit on the back of the staves. I'm not sure what it was. May not have been mold. The odd thing was that two of the staves had it, while the other two did not.

[rfoxmich]

Take the shinai, hit the vendor with it. If they don't say "hey...you hit me with a shinai", discard both the shinai and the vendor.

[Electronegative]

Pages 4-7 of this document sums it up well

http://userpages.umbc.edu/~nam6/maintenance.pdf (http://userpages.umbc.edu/~nam6/maintenance.pdf)