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snap cuts
push cuts
chopping cuts
continuous cutting
power slashes
For now I want to concentrate only on the psycho style power slash. We may discuss the other cuts in subsequent posts. For openers, the power slash will be most effective if it hits the target at the apex of the parabola or just after passing the apex. This point of travel coincides with the highest velocity of the blade. This is also where the knife rounds the corner, so to speak. For those of you who are martial artists, imagine the velocity of an ura ken (back knuckle strike) and how the snapping back of the fist is faster than the striking out. This is important to visualize as I will explain later under the topic of tip speed.
The focus of "The Edge of Functionality, Part 1 & 2" is defining the correct "approach angle" that should be used with each of the three knives described in Part One. I hope the following sketches will provide added clarity.
Knife Example Number 1:
Knife example number one is the straight edged Morris tanto. As this blade approaches the target the tip should be cocked back slightly positing the blade at nearly 90 degrees to the target (and coincidentally about ninety degrees to your arm). Your arm, as it rounds the apex of the parabola beginning its retraction, imparts a curved movement to the straight blade. If by mistake, you strike the target at any angle approaching 180 degrees, blade extended straight out, a straight edge will tend to "bump" into the target and may chop through (if its really sharp) or (not being sharp) will bounce off rather than cut. Practice will quickly show you that the straight edged blade is the least forgiving of the three concerning the approach angle used for cutting.
Example Number 2:
Knife example number two is a good neutral blade design, more flexible in the way it is used. Therefore this would be the best choice for a beginner or someone who is less interested in studying cutting dynamics and more interested in general utility purposes.
The Blackhawk™ Tatang’s medium curved blade makes cutting almost effortless. (I say almost because you still have to worry about a thing called hasuji.) You will note in these three sketches that as blade curvature increases, the approach angle also increases. This is what keeps the tip buried in the target rather than allowing it to pull out. The nearly vertical angle used with the Morris tanto becomes a nearly zero angle with DJ’s extremely curved fighter, example number three. Successfully cutting with that increasing curvature makes the arc of the blade and the hand become more parallel, ie following the same path.
Knife Example Number 3:
Number one and three establish the extreme design limits. Example number three has the most extreme curvature. The best approach angle for cutting with this knife is the one found to be least effective with a straight edged blade. As your blade approaches the target, the highly curved blade and your arm should be nearly in alignment with the blade cocked very little, if any. If you cock this blade back during the cut it is possible that the tip will never even come into contact with the target. This is because the blade edge, and the tip in particular, will be drawn away from the target as your arm rounds the curve and begins to retract. This will become painfully obvious in test cutting when, despite being within physical range, your knife fails to cut completely through the target. You keep moving closer but because your blade is cocked you continue to have problems cutting. Straighten out your arm/wrist and see what happens. In the next blog I will address hasuji and tip speed in more detail.
A fair majority of modern Bowies and fighters have ricasso less than 3/4 inch long. The maker’s name may fit but it does not provide enough space to fit your finger. If you look at the Bowie knives in the photo you will quickly see which ones can accommodate the choked-up grip and which ones cannot. Even with a choil, extending the razor sharp edge all the way to the ricasso makes using a choked-up grip risky. Very little cutting is performed at the extreme back edge of the blade and therefore it would be more useful if the last inch had the edge dubbed off. The problem is, if your knife has a too-small choil you cannot just Dremel™ it out bigger. That’s right we’re talking about grinding on that $600 fighting knife you just bought. While it only takes a couple minutes with a stone or diamond hone to dub off the sharp edge, what are you going to do about the lack of a ricasso? There is a limited solution. Lacking a ricasso, you can invert the knife, primary edge facing upward and place your pointer finger on the back edge of the blade wrapped around the guard. This does change the way the knife feels and sits in your hand but it is an option. In fact, this was a method commonly used by seasoned Bowie knife fighters in the olden days.
Experienced knifemakers like Mike Sturman, Steven Tedford, and Gary Bradburn know the value of a useable ricasso and/or a choil. Mike and Gary are military veterans and know something about handling a fighting knife. Matt Lamey obliged me by adding space for my finger when he forged a fighter for me. Anyway, it is something to think about before ordering your next custom fighter.
By the way, find a good instructor and really learn how to use that knife, then you’ll appreciate the essential ricasso.
Here is a web inventory update. Almost all of our indonesian knives are gone and we will not be replacing them due to supply problems. If you want something please let us know soon! We have more Cobras coming both blasted and black blade versions. They just keep getting better as Brent refines the design.
The Hogosha is GONE!! Honestly you missed one heck of a knife. If you are interested in a pair of chinese swords contact me for an unbelieveable price break. They are new and I originally bought them for myself but I am still too attached to kenjutsu to spend the time learning Chinese sword. I am also going to list a couple hand-forged primitive bowies that are great quality but not highly polished. Again email me for particulars and get a great price before I put them on the website. We still have a few of the ITAC knives left as well. These are top of the line fighting knives that are attractive and fully tactical. I own two of them myself.
If you want a good investment buy an ITAC or one of our reasonably priced Hanwei swords. I wish my 401K held its value half as well.
This custom "Hogosha" tanto by Gary Bradburn features a clay tempered 6.25" high carbon steel blade in the Shobu style with bright hamon 1.25 inches wide at the handle. The handle has dark red rayskin wrap with black Ito, large silver dragonfly menuki on one side and skull crusher pommel. The knife is 12" overall in length and includes a Kydex sheath with adjustable belt loop.