It Doesn't Have to Make Sense: It's Just the Law - Knife Law

A decidedly primitive hunter attracted the attention of game wardens who admired his Stone Age bow and equipment. But his stone knife was a problem. The knife was double-edged, which was authentic for the Stone Age, but a violation of modern state law. The hunter was advised to never carry the dagger again, and warned that the next time he might encounter a more rigid officer concerned with legal technicalities.(1) The hunter thought that he had already met such a person, but perhaps it is a matter of degree.


People who carry guns for defense often carry knives as well. There is a famous picture of a W.W. II British commando showing off his Commando knife. He is also shown to be carrying a "Smatchet" (a heavy fighting knife), a machete, a 17-inch Enfield bayonet, and he probably had a straight razor in his pocket. Such knives are almost never used in combat, but they are comforting.(2) A character in a recent zombie movie brandished a machete and boasted that it would never run out of ammunition. Knives ensure that given the very worst development of the very worst thing, we will not be helpless. Knives are also subject to fewer regulations than guns, but busy legislatures are trying to close the gap.(3)

Knives inspire a primal reaction in the viewer, especially if the viewer sees the business end coming his way. During the bitter fighting for the Pusan Perimeter, a platoon was assigned to seize a hill that had already been hit with artillery, only to butcher the last platoon sent against it. The platoon fixed bayonets and drove the North Koreans from the hill.(4) Prisoners reported that the sight of American bayonets made the difference. A veteran of the First World War’s shellfire and trench raids recorded, "Once when I had a bayonet a few inches from my belly, I was more frightened than by any shell…"(5) FBI profilers have found that sadistic rapists prefer to use knives "because it is so intimidating and causes mental anguish." (6) This association with criminal activity, when coupled with primal reaction, demands that knife owners be discrete in carrying their favored blade.(7) This is not fair, this is not right, this is not just, but this is one reason for the title of this feature.


A knife is typically defined as anything with a point, an edge, or both. This seems to be a straightforward definition encompassing ice picks, razors, axes and cleavers. It also includes awls, scissors, saws and screwdrivers, really. In October of 1942, a correspondent watched a Marine company go into combat on Guadalcanal. Each rifleman carried a bayonet with a sixteen-inch blade. One also fortified himself with a twelve-inch screwdriver with this reasoning: "Never can tell, might lose my bayonet with some Japs in the neighborhood."(8) Courts have labored long over screwdrivers, scratch awls, keyhole saws and similar tools, only to fall back on a blood test. If the user carried the tool in order to shed blood, then it was classified as a weapon. The purpose of the tool’s manufacture is not especially important to this analysis. In one case, a threat accompanied by a butter knife converted the butter knife into a weapon. This was a kitchen butter knife, not a butterfly knife.(9) One defendant was convicted of carrying a concealed weapon, specifically a pair of scissors (two points).(10) The defendant claimed to be carrying them to cut the hair of another resident of his government housing complex. The fact that the government housing complex was a state prison was not described as a factor in the decision, but doubtless played a role in the charges.

The specific style or type of knife often becomes an issue. Pocketknives usually suffer fewer restrictions, but not always. Missouri considers all knives to be weapons, except for "ordinary pocket knives with a blade of four inches or less." (11)The statute does not define an "ordinary" pocketknife. The Oregon Court of Appeals, in defining identical language, ruled that the term "pocketknife" was a folding knife that fits in a pocket "and until a defendant arrives with a folding machete and a long pocket, the term is not likely to be a primary cause of concern." The term "ordinary" was more difficult. Because it was difficult it was vague, and therefore unconstitutional. The statute was rewritten to allow all folding knives which fit in a pocket.(12) There actually are folding machetes and large pockets, but they have yet to reach appellate courts.


Federal law excludes from the definition of "dangerous weapon" any knife with a blade less than two and a half inches long.(13) This means that box cutters are not deadly, although experience shows us that they are.(14) The statutes do not specify how to measure a blade, but a straight line at right angles from the hilt is the most straightforward. Some states ban carrying double-edged knives. California is terrified that its citizens might carry "dirks or daggers" and bans carrying both styles. The California Supreme Court ultimately decided that the statute could be violated by carrying concealed "steak knives, scissors and metal knitting needles…but there is no need to carry such items concealed in public." (15) Not only are Californians prohibited from carrying virtually any type of concealed knife, but grandma had better look out too.

Knives with saw blades or serrated edges for cutting rope or seat belts are often assumed to be designed for causing unusual damage to human flesh. Knife owners should be aware of this prejudice and stress the rescue and utilitarian value of the design. The useless "blood grooves" are sometimes taken as proof of savage intent.

In 1950, an article in Women’s Home Companion began a campaign to outlaw switchblades "for the children." Federal law prohibits switchblades and defines them as a folding knife which opens by pressure to a button or other device.(16) This does not require the button to release a spring. The knife that kicks the blade out by a cam-action is as much of a switchblade as anything in West Side Story, advertisements of "legal switchblades" notwithstanding. There are "assisted opening" knives which are partially opened like an ordinary lock blade, and then a spring fully opens the blade. As switchblades are called "automatic" knives, these can be called "semi-automatic" knives. Assisted opening knives do not appear to be treated as switchblades at this time.


Federal law includes gravity knives in the definition of switchblades. It also bans knives which open by "inertia." This and a number of state laws referring to "centrifugal force" appear to be attempts to restrict or ban butterfly knives. Consultation with a physics professor raises the question of whether these laws successfully describe butterfly knives, but only a question. Federal courts have explored the issue and found that butterfly knives are switchblades because they were marketed as weapons and did not have "utilitarian" blades.(17) The number of recently imported butterfly knives indicates that customs has now found more serious threats.

Federal law also prohibits a "ballistic knife," a device which throws a blade some fifteen feet by spring action. The device is reputed to be an invention of Soviet Special Forces (Spetsnatz) in the "Evil Empire" days. Its heritage may explain why the device was barred from importation. It is interesting, however, that Soviet guns were not barred, only this knife.
Federal knife law only applies to federal property and importation. State and local law will be the only knife regulation most people will encounter. State preemption statutes typically do not cover knives, and some local governments have attempted to protect us from walking with sharp objects.

A peculiarity of some concealed weapons licenses is that they are not concealed weapons licenses; they are concealed handgun licenses. In such states, license holders cannot carry concealed knives, at least those that qualify as weapons. High capacity magazines and .500 Magnum revolvers are legal to carry concealed, but a fighting knife is not. It doesn’t have to make sense; it’s just the law.


CZ International is based in Kansas City, Kansas, and in celebration of the end of the "assault weapons" ban introduced a bayonet for its excellent CZ 75. But Kansans cannot mount them on their concealed guns. Kansas is a handgun only state. Neighboring Missouri has a concealed weapons license which is valid in Kansas, but Missourians have to take the bayonet off of their CZs when crossing the line. A Kansas concealed handgun license and all other concealed carry licenses are valid in Missouri, and they can mount their bayonets when they visit. It doesn’t have to make sense; it’s just the law.

1. Bulletin of Primitive Technology, Spring 1998, No 15 at 6.
2. I have a Viet Nam era knife with six unexplained notches on the back of the blade. If R. C. Bolen is out there, I’d love to talk.
3. See Wong Esq., Knife Laws of the Fifty States, Bloomfield Press, Scottsdale AZ, 2007.
4. Mack Col (ret), Memoir of a Cold War Soldier, Kent State University Press, Kent Ohio, 2001 at 61.
5. Lord Moran, Anatomy of Courage, Avery Publishing Group Inc, Garden City Park NY, 1987 at 69.
6. Douglas & Olshaker, Obsession, Pocket Books NY. 1998 at 110.
7. The United States Knife & Tool Association fights to protect the rights of knife owners. See
8. Hersey, Of Men and War, Scholastic Book Services NY, 1963 at 33.
9. State v Tankins, 865 S.W.2d 848 (Mo. App. E.D., 1993).
10. State v Quinn, 647 S.W.2d 166 (Mo. App. W.D., 1983).
11. RSMo 571.010 (9).
12. State v Harris, 594 P.2d 1318 (Or. App., 1979).
13. 18 U.S. Code section 930 (g) (2).
14. A client’s daughter was killed when she tried to mediate a dispute between two 16-year-old girls. One slashed her throat with a box cutter. Peacemakers may be blessed, but they do not always survive.
15. 15 U.S. Code section 1241 et seq.
16. Taylor v United States, 848 F.2d 715 (6th Cir., 1988).


This information is for legal information purposes and does not constitute legal advice. For specific questions you should consult a qualified attorney.

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