The U.S. Constitution forbids vague penal statutes. The principle is succinctly stated in the case
of Grayned v City of Rockford, 408 U.S. 104 (1972):
It is a fundamental principle of due process that an enactment is void for vagueness if its prohibitions are not clearly defined. Vague laws offend several important values. First, because we assume that man is free to steer between lawful and unlawful conduct, we insist that laws give the person of ordinary intelligence a reasonable opportunity to know what is prohibited so that he may act accordingly. Vague laws may trap the innocent by not providing fair warning. Second, laws must provide explicit standards for those who apply them to prevent arbitrary and discriminatory enforcement. A vague law impermissibly delegates basic policy matters to police officers, judges, and juries for resolution on an ad hoc and subjective basis, with the attendant dangers of arbitrary and discriminatory application.
Criminal penalties are imposed under the laws of many U.S. States based on terms referring to knives such as: “ballistic,” “bowie,” “butterfly,” “dirk,” “gravity,” “poniard,” and “stiletto.” The terms are undefined in most instances. Some of the terms are not susceptible to a reasonably definable limit. In some instances, legislative definitions are poorly written.
Despite the long-standing void for vagueness doctrine, admittedly defective and confusing definitions – as applied to knives – have been upheld.
In People v Ortiz, 479 N.Y.S.2d 613 (1984), a municipal ordinance was challenged as vague and overbroad. The New York court upheld the ordinance and stated:
Of course, a perfect definition is an impossibility; what the City Council has attained is reasonable precision. An affirmative defense is provided if an occasional angler or hunter should fall victim to this Local Law.
The Ortiz decision concedes that the definition is faulty and condescendingly suggests that since only fishermen and hunters may “fall victim” and that they may raise an affirmative defense, imperfection is acceptable.
This decision is precisely what is forbidden by the Constitutional void for vagueness doctrine. The New York Ortiz case is not an isolated occurrence. In City of Seattle v Riggins, 818 P2d 1100 (1991), the Washington Court of Appeals quoted approvingly the above passage by the New York court in Ortiz as authority and precedent for upholding an imperfect law.
The American Knife and Tool Institute (AKTI) is a 501(c) 6 nonprofit organization representing all sectors of the knife industry. We suggest that imperfect definitions should not be tolerated for any reason, including that only some disfavored group will “fall victim.” We offer these definitions for knife designs or knife styles as a part of our mission to educate and inform members of the knife community and the public, legislative, and law enforcement entities about knives and matters regarding knife laws. Our goal is a more perfect set of definitions and the avoidance of the arbitrary and discriminatory application of the law.
Various laws concerning knives involve a blade length. However, there is an extremely wide variety of blade shapes and handle shapes. In the absence of an objective and standardized method for determining blade length, there is the possibility of inconsistent enforcement. AKTI has developed a Protocol for Measuring Knife Blade Length.
Also see: Understanding Bias Toward Closure and Knife Mechanism
- Automatic Knife
- Ballistic Knife
- Bias Toward Closure
- Bowie Knife
- Butterfly Knife or Balisong Knife
- Effective Cutting Edge
- Gravity Knife
- Inertia Knife
A knife with a blade exposed in an automatic way and moved from the closed position to the open position exclusively by potential energy upon release of a restraining mechanism.
Comments: Automatic knife is a term used to refer to a specific knife type based on functionality. Within the knife industry, “automatic knife” is the preferred term for what is often imprecisely and pejoratively referred to as a “switchblade.” The distinguishing aspect of an automatic knife is that it uses only stored or potential energy to move the blade, which is typically biased or “spring-loaded” to the open position and held closed by a mechanism released by a trigger. That energy becomes “stored” by compressing a spring when manually pivoting the blade to the closed position. The only manual force involved in the automatic opening operation is applied to the release control – typically a pushbutton switch on the handle – thereby allowing the blade to move.
In 2007 New York State created a statutory definition (§ 265.00 5c) for “automatic knife”:
‘Automatic knife’ includes a stiletto, a switchblade knife, a cane sword, a pilum ballistic knife, and a metal knuckle knife.
The definition was part of a convoluted legislative process to allow for a knife museum, as revealed by the legislative history of the 2007 amendment, which created the category.
Legislative intent. It is the intent of the legislature to facilitate the establishment of certain museums that are dedicated to cataloging, inventorying, exhibiting or displaying cutlery and knives made in New York State. This act will particularly help municipalities and interested groups located in the Hudson valley, which has a long history of manufacturing knives, to establish a cutlery and knife museum to offer for public display or exhibition of, among other exhibits, certain automatic knives. During the early twentieth century, the counties of Orange, Sullivan, and Ulster manufactured approximately fifty percent of all knives manufactured in the United States. There are persons who are interested in local history and are planning to establish a local museum to display all the various kinds of cutlery and knives that were manufactured in the Hudson Valley and throughout the United States. However, while certain military and police personnel and those who hold a hunting or fishing license are able to legally possess certain automatic knives, museums and other institutions, incorporated for the promotion of art, education, history, and science, are not legally permitted to possess or own such artifacts. This act remedies this situation in a way that still places these knives in a secure environment and out of general circulation.
The Wawarsing Historical Society was allowed to establish a knife museum in Napanoch, New York. Wawarsing Historical Society and Knife Museum’s website is www.theknifemuseum.com.
While the statement of legislative intent claims to have remedied the dilemma presented, it created an opportunity for confusion. The § 265.00 5c automatic knife definition should be understood and applied only in the New York State museum exception’s unique context.
A knife with a detachable blade that is propelled by a spring-operated mechanism.
Comments: Ballistic knives are restricted in many U.S. states, including, but not limited to: CA, CO, FL, IA, IL, MA, MD, NC, NJ, OH, and MA. The knives are referred to as a “shooting knife” in Maryland and a “spring-loaded projectile knife” in North Carolina. The simple unauthorized possession of such a knife is a Class D felony in Iowa.
The term “ballistic knife” does not apply to the items designed or marketed as “throwing” knives, which do not feature a detachable blade propelled by spring action.
Bias Toward Closure
A tendency to remain in the closed or folded position, imposed by a spring or mechanical load, unless acted upon by manual force.
Comments: A bias toward closure with folding or moveable blade knives obtains when a force or load imposed on the blade causes it to remain in the closed position. Additional information and graphic illustrations are available on this website. See Understanding Bias Toward Closure and Knife Mechanisms.
Bowie Knife (Not reasonably definable)
Comments: While “bowie” restrictions persist in ten U.S. states and the District of Columbia, AKTI suggests that the term “bowie” is imprecise and beyond definition consistent with Constitutional due process. “Bowie” or “bowie knife” does not identify characteristics sufficiently to enable persons of ordinary intelligence to differentiate between lawful and unlawful conduct. The term “bowie knife” came into use in the mid-19th century as a marketing term. It remains in common use and is casually applied to a broad range of fixed blade knives without common characteristics apart from a sharp edge and blade that tapers to a point.
Butterfly Knife or Balisong Knife
A folding knife that incorporates two handle pieces that pivot from the tang or rear of the blade that encase the blade in the closed position and counter-rotate to form the handle when in the open position.
Comments: Balisong and butterfly are used interchangeably and refer to a specific knife type based on functionality. Butterfly knives are prohibited in Hawaii by that name. Restrictions on butterfly knives obtain in New Mexico, where the state “switchblade” restriction has been construed to apply to butterfly knives. The distinctive feature of a butterfly knife is two handle pieces, each with a pivot. The distal ends are held together, when closed or opened, by a simple latch.
Some individuals acquire, through practice, the ability to manipulate and open a butterfly knife in one hand. A butterfly knife does not simply fall open by gravitational pull. Instead, gravity – or centrifugal force – must be redirected in sequenced movements to achieve one-hand operation. Butterfly knives are not “gravity knives.” That training butterfly models with unsharpened edges are produced and sold for practice indicates that one-hand operation is more a matter of acquired skill on the part of the user than the inherent design of the knife.
A knife having a generally straight fixed blade with dual effective cutting edges.
Comments: Statutory restrictions based on the noun “dagger” obtain in 50% of the U.S. states. Most of these proscribe concealed carry.
Daggers typically feature a crossguard or quillon, dual symmetrical cutting edges, and a blade tip positioned on the center axis of the handle. The purpose of the crossguard is to enhance the safe use and carry of the dagger.
The California penal code provides a definition for “dirk” and “dagger.” The California Supreme Court has observed that the priority in drafting said definitions was the ease of prosecution instead of providing persons of ordinary intelligence a reasonable opportunity to know what is prohibited so that they may act accordingly. The Supreme Court of California in People v Castillolopez, 371 P.3d 216 (2016) stated the following about said statutory definition:
In 1993, the Legislature undertook the first of several efforts to supply a definition of “dirk or dagger.” In its initial effort, the Legislature defined “dirk” or “dagger” to mean “a knife or other instrument with or without a handguard that is primarily designed, constructed, or altered to be a stabbing instrument designed to inflict great bodily injury or death.” . . . But this definition ‘ultimately proved too narrow and too difficult of proof. Prosecutors complained that “since we can never show that the primary purpose of a butcher knife, hunting knife, survival knife, ice pick, etc., is to cause death or great bodily injury by stabbing, we cannot obtain convictions under the statute, even when the person was carrying the concealed instrument for potential use as a weapon.” (citations omitted).
We suggest that the California definition for “dagger” and “dirk” is intended to prioritize conviction and allow – if not facilitate – arbitrary and discriminatory application. Accordingly, it is inconsistent with the Constitutional due process requirements as recognized by the U.S. Supreme Court decision in Grayned v City of Rockford, 408 U.S. 104 (1972) mentioned above.
Dirk or Dirk Knife (Not reasonably definable)
Comments: It is the position of AKTI that the label “dirk” is too vague. The term does not provide sufficient guidance to determine what is and is not a dirk. See the above comments relative to “dagger” regarding the California definition of “dirk.” See also the article from the May 2020 edition of Knife Magazine entitled “The Misunderstood Dirk.”
A knife having dual effective cutting edges.
Effective Cutting Edge
A cutting edge capable of performing ordinary, cutting tasks associated with, but not limited to, activities such as meat cutting, culinary arts, surgery, farming, animal husbandry, building trades, gardening, pruning, hunting, fishing, or any craft.
Comments: Some U.S. states – notably Michigan and Massachusetts – have enacted restrictions applicable to “double-edged” knives. In Michigan, it is a felony punishable by up to five years imprisonment and a fine of $2,500 to carry a double-edged stabbing instrument in a concealed manner. AKTI suggests that individuals must be able to reasonably ascertain what constitutes an edge. Many knives that feature a “swedge” or “false edge” should not be included in the “double-edged” category.
An effective cutting edge will typically need to be resharpened from time to time, depending on use. A “false edge” or “swedge” is neither designed nor intended to cut and requires only the same maintenance as the non-cutting aspects of the blade. An effective cutting edge may be serrated. A “saw tooth” edge, as seen on the spine of the U.S. Air Force survival knife and various similar knives, is intended for ripping the aluminum skin of a downed aircraft and is not an effective cutting edge.
Examples of “knives” without an effective cutting edge include letter openers, butter knives, oyster knives, palette knives, and throwing knives.
A knife where the blade may be extended and retracted exclusively by gravitational force.
Comments: The blade of a gravity knife may be opened by holding it in a tip-down, roughly vertical attitude and releasing the lock mechanism. The knife remains in the tip-down attitude throughout the opening. “Gravity knife” technology is feasible with “out-the-front” designs where the blade falls open without a change in the attitude of the knife relative to gravitational pull. A folding knife typically has a blade that pivots in an arc of 180 degrees. Such a knife cannot fall from closed to open without a shift in attitude or manipulation to redirect gravitational force relative to the blade’s angle and the handle.
World War II German parachute forces (Fallschirmjager) identified the need for a self-rescue knife that could be operated in one hand under challenging circumstances. Possible uses of such a knife would include cutting entangled suspension lines or the parachute harness. The answer to this requirement was an out-the-front design with minimal reliance on mechanical components subject to malfunction or failure. A simple lever-actuated lock allows the blade to fall open or fall closed.
There was a time in the post-World War II period extending into the mid-1950s when souvenir German military paratrooper’s knives brought back to the U.S. were common. The term “gravity knife” occurs within the legislative record concerning the 1958 Federal Switchblade Act with specific references to the World War II German paratrooper or Fallschirmjager knife. The knife was targeted by the “Switchblade Act” because of its one-hand operability.
Gravity technology knives have been produced by a few other manufacturers but are now uncommon. Eickhorn-Solingen Ltd., a successor to one of the World War 2 Fallschirmjager knife manufacturers, still makes a model intended “especially for rescue teams” using the same basic operating design. The manufacturer’s website states: “The blade can be opened with one hand, even with gloves, without any danger to the hand.”
See Comments relative to Gravity Knife.
A weapon featuring a metal shaft with a generally square or equilateral triangular cross-section typically 10 to 15 inches in length, tapering evenly to a point fitted with a point fitted with a cross-guarded hilt.
Comments: A stiletto lacks effective cutting edges. The stiletto was developed in the 15th century in response to chainmail and plate armor in use at that time. The slender shaft could be forcefully wedged through interstices in the armor to inflict a puncture-type wound.
Switchblade Knife (See definition for Automatic Knife)
Comments: The term “switchblade knife” was originally understood to describe what we define as an “automatic knife.” AKTI suggests that the use of the term should be avoided unless it is in connection with a statute that uses the term. Where the term occurs in a statute without a definition, AKTI suggests that the “automatic knife” definition as promulgated by AKTI should be adopted.
Pennsylvania and Massachusetts enacted automatic knife restrictions without using the word “switchblade.” Most states that enacted statutory definitions for “switchblade,” or a variant term such as “springblade” (WA § 9.41.250), included within those definitions knives opened by gravity, inertia, or a combination thereof.
Federal law 15 U.S.C. § 1241 (b) provides:
The term “switchblade knife” means any knife having a blade which opens automatically–
(1) by hand pressure applied to a button or other device in the handle of the knife, or
(2) by operation of inertia, gravity, or both.
Inertia is generally defined as a property of matter by which it continues in its existing state of rest or uniform motion in a straight line unless that state is changed by an external force. The blade of a folding knife in a closed state will remain closed unless acted upon manually generated force.
Many folding knives, including manual slip joint designs, may be opened by a kinetic “wrist snap” movement. This fact was infamously exploited by prosecutors in the New York City metropolitan area for several decades until May 2019, when the “gravity/centrifugal force” knife prohibition was repealed through the efforts of AKTI and others.
Understanding Bias Toward Closure and Knife Mechanisms | Protocol for Measuring Blade Length
Articles regarding specific knife legal issues can be read in Resources
Version 2021, Adopted 2005.