Follow Up Testing of Zhengwu Swords

This forum is for posting Chinese Swordsmanship product test results conducted by Center Director, Scott M. Rodell. Any manufacturer may submit a product for testing.

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Scott M. Rodell
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Follow Up Testing of Zhengwu Swords

Post by Scott M. Rodell » Thu Oct 25, 2007 2:01 pm

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Follow Up Testing of Zhengwu Swords
http://www.zheng-wu.com/

I've recently spent more time cutting with four different Zhengwu Swords, 2 Yinlong Jian, 1 Qing Dao and a Miaodao. I have been working on the final edit of my latest work, "A Practical Guide to Test Cutting for Historical Swordsmanship" & thought it a good time to get in some extra practice. And to be fully forth coming, we at Seven Stars Trading (my company), have been considering adding Zhegnwu's line to our offerings. We have been impressed with the improvements Zhengwu has made in the fit & finish of their swords since I first tested one of their jian several years ago. Unfortunately, my most recent test cutting exposed a number of problems with the blades that require correcting.

The sword tests I preformed in the past included cutting live bamboo, usually about 1 1/2" in diameter. Zhengwu's swords cut these no problem. The more recent test cutting included cutting the bottoms of 2 - 2 1/2" bamboo stalks and 1 1/2" stalks wrapped in a single rice straw mat. A seasoned practitioner would not find these to be particularly demanding targets, though they are a degree tougher than the bamboo stalks cut earlier with Zhengwu swords. During the most recent cutting, three probelms came to light.

The first problem was that the hilt of one of the Yinlong Jian came dangerously loose during structural testing after a very few light cuts. Indeed it is likely that this hilt would have come loose with vigorous form practice alone. I reported this to Mr. Zhou (owner of Zhengwu). He sent me a replacement jian with two improvements: adding a second pin in the grip that travels thru the tang & adding a second nut to the pommel end. This correction solved the problem, but it brought a second concern to light. That is that the hilt of each sword in my possession was secured differently. This brings up questions about consistency during production. I'll return to this question later.

The third problem is of greater concern. That is that every Zhengwu sword I cut with bent & took a set easily. It should be noted that all good swords will bend. Obviously, it is better for a sword to bend instead of break. Having said this, the Zhengwu swords tested bent & took a set too easily. For example, the Qing Dao, which by the nature of its thicker cross section should have been more resilient than the jian, actually bent more than the other Zhengwu swords, 5 degrees off straight. Given the relative overall softness of the these blades, they are easy to straighten, but a bend of 5 degrees does requite one to suspend practice & head to the work bench to straight the blade.

To discern exactly what was the underlying weakness causing these blades to easily bend, I had the blades sectioned & a metallurgical analysis preformed. This sectioning brought another problem to light, that I will come to in a moment. The short answer as to why the blades bent is than given the kinds of steel used, the ratio of harder, spring edge plate steel to soft body steel is too low. The hard edge plate steel was quite thin. This meant that during the shock of cutting, the thicker soft steel that wants to bend, essentially over powers the harder core steel that wants to spring back to shape. Also the heat treating used did not compensate for this & was different sword to sword.

The other problem the sectioning brought to light was that in the case of one jian blade, the edge plate did not extend edge to edge. Instead of traveling straight thru the center of the blade from one edge to the other, it was a lazy "S" shape & came thru not at the edges but at the blade flat on each side. Be that as it may, the .4 carbon steel at the edge has still tough enough & held up to cutting.

Overall, the problems outlined here, as well as differences in temper, etc, give one real pause. Clearly there is a problem with consistency & quality control at Zhengwu that need to be addressed. When these problems were related to Mr. Zhou Zhengwu, he explained that each sword was made by a different artisan at his factory. He also said he would send another jian for testing that would not bend during cutting. I have not received this jian as of yet, but will certainly put it to the test when it arrives. In the meantime, I hope this information is of use to Zhengwu & wish them well in improving their products.

In summation, Zhengwu swords, as presented for testing, make excellent swords for forms, basic cut and soft target cutting practice. They can also be used on tougher standard target material such as rice straw mats & green bamboo, but the user will have to be deal with the annoyance of regular blade straightening. Naturally, I would rather see the resiliency of the blades improved. Given the level of improvement we've seen from Zhengwu over the past few years, this appears to well within their abilities.[/i]
Last edited by Scott M. Rodell on Sun Oct 28, 2007 3:49 pm, edited 1 time in total.

Scott M. Rodell
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Yinlong Jian Blade Hardness

Post by Scott M. Rodell » Fri Oct 26, 2007 8:53 am

The blades of the 2 Yinlong Jian used in this recent follow up test cutting discussed above had different hardnesses in the cutting region:

The hardness of the more springy of the 2 jian was found to be-
edge 55 - 56Rc
midway to ridge 42 - 46
ridge 45

The hardness of the softer jian of the 2 jian was found to be-
edge 48Rc
midway to ridge 42
ridge 40

Both of these swords were softer at the forte.

Scott M. Rodell
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Zhengwu Sword Safety Concerns

Post by Scott M. Rodell » Fri Oct 26, 2007 9:00 am

I received a number of emails since posting this review concerning the safety of using Zhengwu swords. Without examining & testing a specific sword, I can not attest to that particular sword's structural integrity. Each & every sword used for cutting or serious training of any sort should be tested for structural integrity by its owner, that is the owners responsisblity. Even the best smith can on occasion produce a sword that has an unseen flaw that could prove a hazard to the user. Having said this, excluding the one Yinlong Jian that the hilt came loose on, I have not seen anything to indicate that Zhengwu's swords are unsafe for practice.

Updated 12/20/07
Please see the recent thread: Zheng Wu Long Yin Jian
(viewtopic.php?t=628) for a review of a jian sent by Zhengwu in response to the follow tests discussed above.

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