But what makes a good fighter?
Besides high quality steel, rapid deployment, and no-shit bombproof durability and mechanical reliability, there are numerous edge and blade designs all touted as the best thing since sliced bread for slicing up an attacker.
Take Notice: I don't know dick about grinds. That's for another discussion with someone far more qualified than myself.
This covers blade shape and number of edges.
These make great general purpose blades. My Benchmade 615 Mini Rukus (now discontinued, which sucks because it's probably THE knife I'd carry if I could only have one.) is a drop point and I use it for everything. A drop point cuts pretty well and isn't bad for stabbing, although the latter is not it's strong suit. If you're looking to "defang the snake" a drop point is an excellent choice. If I were carrying a purpose-driven offensive blade, this would not be my choice. These are nearly always single-edged which is very beneficial in a fight as the spine can be used for trapping or entangling an opposing limb.
Clip Point:
Bowies and Ka-Bar's are clip points. These are essentially a drop point that has been "clipped" near the point. In some blades, this clip is (or can be) sharpened so it will penetrate better on a thrust than a drop point as, assuming the clip is sharpened, you effectively have a double-edged blade for the first portion of the blade, and this usually runs for two inches or so. This allows for a devastating "Back Cut" where the first few inches of the blade's spine cut into the attacker. This is a really easy way to spill an attacker's guts all over the pavement... and was used very effectively by bad and good men wielding bowies over the years. However, unlike a fully double-edged blade, there is still a spine that can be used for entangling or trapping. A clip-point is a very good choice for a dual-purpose work knife that pulls duty as an anti-personnel blade.
Tanto Point:
The big sell for a tanto point is it's piercing ability... so much so that a tanto point will zip through soft armor. LEO's should be wary of this... After all, they were designed to be used to pierce armor in feudal Japan... and they still do. Blades like the Cold Steel Kobun, Emerson CQ-7B, and the Benchmade Presidio and AFO2 (also available as drop points) are examples of this CLASSIC blade style. They are usually single-edged, so one has a spine to entrap with. That said, trying to clean your fingernails with a Tanto might not be the best idea. Due to their piercing point, they aren't the best work knives, but they'll do.
Wharncliffe or Modified Wharncliffe:
Basically a reversed Tanto, these make very good thrusters.... The Norseman's Scramasax, Spyderco's Yojimbo, Blackhawk's Be-Wharned (both designed by no more devious a mind than Michael Janich of Martial Blade Concepts), Benchmade/HK's Instigator,and TSD Combat Systems' Gang Unit and Grab And Stab blades (DEFINITELY nice knives and on my list) are examples. While they aren't bad work knives (being single edged), I can tell you from experience with a Be-Wharned, they lust for blood... and are best suited to uses where they get to draw it. With their edge being longer than their spine, they offer vast amounts of cutting power and a very good level of penetration for a single edged blade. On trapping, some are better than others. If they are more angular and resemble a flipped tanto blade, trapping is fine. If they have a curved point, be mindful that a limb may slip off of it.
Hawkbill/Karambit:
I LOVE Karambits! Let me say that again... I have an unhealthy love affair with a Karambit. They are designed after a Tiger's claw, and they cut like one! These things WANT, NEED, and MUST HAVE BLOOD! I carry a 5.11 "Curved Utility Blade" (folding karambit) and there is nothing utilitarian about it. Understand, if you trap with a Karambit, which they are VERY good for, what you trap should be ensconced within the cutting edge... and it won't be pretty for what you trap. I prefer using a karambit in a reverse grip, edge out, and actually keep one on my thigh rig. Be advised: Many jurisdictions forbid carrying a hawkbill (a Karambit without the ring) and that includes the karambit. However, I don't care about legal... Mine is only worn when I get the chance to do bad things to bad people... That said, if they're legal in your AO (or you just don't care.... Big Boy/Girl rules apply!!!) you won't be served ill using one as an anti-personnel blade. The tell-tale ring of a karambit makes them VERY fast to deploy as well.... Especially if it's an Emerson with the Wave feature. LEO's, if you can, putting one on your non-gun side positioned for a reverse grip, edge out deployment makes for a weapon retention tool that can't be beat... but if your Chief sees it they may have a stroke, coronary, aneurism, and heart attack all at the same time.
Spear Point:
These can be found as a single or double-edged blade. As the name implies, they're good piercers and cut pretty well, but their strong suit is piercing. I wouldn't call a spear-point blade a working tool at all.... especially if it's double-edged. Due to coming to a very sharp point, they aren't the best in the world for trapping as the spine's slope usually starts pretty early and while trapping can be done it won't be as effective as a flat spine. Most double-edged knives are a spear point blade.
On Edges: Single or Double?
I own both double and single-edged knives and there are a very few double-edged blades that are legal to carry but I do own and carry one (Benchmade SOCP... it's edges are so short they skirt most laws on the subject) that is... And I get asked which one people should get (reference one edge or two) and the short answer is this:
What's the knife's intended use?
Is it a work knife?
A "defensive" knife? (I hate that term... it's a tool. How it's used determines offensive or defensive)
A cutter?
A killer?
Double duty as a work knife and anti-personnel blade?
Straight up... A double-edged blade is best suited for killing... And there is a place for those kind of tactics in your self-defense arsenal. A knife used to slash or cut will not have the same "terminal ballistics" (if you will) as a knife used to thrust or stab. That simple. An incision is fixed with stitches and surgery. A thrust or stab is penetrating trauma and more akin to a gunshot wound. Take from that what you will.
I like a double-edged blade. I think they're cool and their method of use works well with my own personal training and skill-set when it comes to edged weapons. I just wish I had more legal options in double-edged blades for carry in my AO.
To help you in any decisions, I am attaching a list of Pros and Cons for each. Take from them what you will.
Single Pro:
-Good for trapping
-Typically legal
-Most Karambits are single-edged
-Make good dual purpose blades
-Nearly all folders are single-edged
-More robust (tougher) point
-Thicker (tougher) blade stock
Single Con:
-Not as good a penetrator as a double-edged blade
-Doesn't cut entrapped limbs in any orientation.
-If attacker is wearing soft armor or just thick clothing, these do not perform as well
-Thicker blade stock doesn't slip under ribs as easily
Double Pro:
-Awesome penetrator
-Armor? Heavy Coat? No problem.... just hit hard enough
-Cuts on both sides
-What is trapped is cut if a fully double-edged blade
-Usually thinner blades (fits between the ribs easier)
-Blades usually feel more "alive" in the hand
Double Con:
-Nearly guaranteed illegal in almost any jurisdiction
-Only suited for anti-personnel use... and best suited for offensive use.
-Their superb penetration makes them near useless for chores
-Typically more fragile point... as it is thinner, yes, it penetrates easier but if you drop it that point is as good as done.
-Thinner blades
-Cuts on both sides... An attacker may wince out of a trap that isn't as thoroughly entangled as it should be
-Did I mention if you carry one, you'll probably earn a stay in the iron bar hotel with three hots and a cot?
-Very few folders are double-edged. Since it cuts on both sides... if that edge isn't fully covered it doesn't know the difference between your favorite Wrangler's, your leg, and your attacker/target.