Lex Parsimoniae


When it comes to tactical problem solving, we do well to hone Occam’s Razor.

Lex Parsimoniae, or the Law of Parsimony, is paring our approach to the simplest assumptions and most direct solutions. This applies even more so with the high jeopardy and high consequences attaching to tactical applications.

In utilizing the Law of Parsimony to assess combatively effective methods, hoplologist Liam Keeley once identified four desirable qualities: Efficiency of Technique, Economy of Technique, Parsimony of Technique, and Integration Across the System. (1)

We’ll look at each of these each in turn:


Efficiency of Technique

Technique must be both bio-mechanically efficient and behaviorally appropriate – that is, combat effective, recognizing that there is a difference between pure bio-mechanical (technical) efficiency and combat efficacy, for “combative parameters may dictate that movements are not as bio-mechanically efficient as they could be because of other factors…” ( p. 135 )

Similarly, movements that are efficient in one domain may not be so in another situation. Recently I was sent a video of an instructor, on a range, demonstrating a weapon retention technique where he held an attacker’s arm in place while the latter grasped the pistol in the instructor’s front waistband, thus keeping the attacker from taking the handgun.

Applied in demonstration mode, with no countervailing efforts opposing, the technique appeared sound. It was a solid two-on-one hold on the arm, and the pistol could not be taken and brought to bear on the instructor. For the sake of discussion, I’m assuming he was able to prevent the partner from sliding a finger inside the trigger guard and performing a ballistic vasectomy with the gun still in the waistband, something that could very easily happen in that kind of “gun grapple.”

Yet when the instructor tried to demonstrate the technique against opposing will, he ended up not only beneath his attacker, (on two different tries), but gave them dominating pins at his back with his own face down,  leaving them free to use an unfettered hand with strikes to the face or repeated elbows to the back of his head, respectively. While still holding on to his pistol. The instructor, battered and bloodied, apparently maintained that he had successfully retained his weapon, so it was a validation of the technique.

Of course the weapon was retained. In the absence of all other factors involved, the technique was effective, I suppose, under that narrow definition.

In reality, he would have been beaten senseless, and the attacker would have simply taken the man’s firearm after having done so. So weapon not, in fact, retained.

Or, the attacker would have accessed his own weapon with his free hand, and the results would have been quite different.

Efficiency, and efficacy is based on combative parameters in total.

Many jiujitsu techniques are highly efficient and practical under sport grappling rules, yet become far less desirable and less effective where the purpose is different, such as in arrest-and-control or combat situations where the adversary can hit, grab your weapons, use their own weapons, or repeatedly smash your head into a curb.


Economy of Technique

Simplicity of movement – that is all extraneous movement is eliminated and the number of techniques is kept to a minimum. ( p. 138 ) Moreover, extraneous exertion in technique through improper use of musculature, posture, and positional dynamics is reduced.

Economical techniques should be easily usable even when wearing armor,  when carrying heavy gear, in confined quarters, and on uneven or unstable terrain.

Techniques that are not economical – and remember, from a combative standpoint – are those which are not so efficient when the above elements are added.

Some individuals wonder why combative systems, as opposed to performance arts or holistic self-development methods, often offer relatively parsimonious technical curriculae. The reason is in part, Economy of Technique.


Parsimony of Technique

Moreover, it is “better to have a few techniques that always work than dozens that only sometimes work, or only work in part.” ( p. 138)

Once again, this is situationally anchored and goal dependent. What are we trying to accomplish and under what circumstances?

Who are the people being taught, and to what end?

This also allows a refinement of these few techniques (and the more critically important understanding of their principles, body mechanics, pressure testing and validation ) to a higher level than if one were to have to practice dozens to a lesser degree. This allows a greater reliability under added stress and pressure for the few, rather than the many. Which defines Occam’s Razor.


Integration Across the System

“Basic techniques…   … must be transferable, i.e. there should be substantial carry-over in that both the same physical techniques can be done with different weapons and that incoming attacks by different weapons can be dealt with using the same techniques. Moreover,  the techniques themselves need to be sufficiently flexible to be able to be used effectively by a wide range of body types.”

Martial artists may not be aware that this applies in firearms training as well. A fighting platform is a fighting platform and body mechanics are body mechanics. If one embraces a shooting methodology that demands a radically different posture and operating system than empty hand fighting, (assuming also a validated empty hand method), one is cross training in the wrong way.

Flexibility is not relegated simply to application across body types, but to an ability to operate flexibly across multiple combative domains.

In some classical systems,  there is an overall approach to combat: the same physical platform, a common way of moving, and even common techniques are shared across seemingly discrete elements of the curriculae.

Some of these systems with ostensibly large catalogues of technique actually have far fewer than appears on the surface, as often similar methods are used system-wide, responding to differences in the spatial and positional relationships of the combatants, weapons used, and situational variables. Many of these techniques are also linked to others so that when one is countered, another from elsewhere in the system is readily transitioned to.


“Reductionist and Congruent”

Shivworks ECQC instructor Craig Douglas applies Occam’s Razor to modern combatives,  and refers his approach as Reductionist and Congruent. If training in a certain way in stand-up fighting, and then when on the ground a complete re-boot is necessary, the system is not integrated. For combative systems intended for actual in extremis conditions, practitioners must seek congruency across platforms and reductionism (and consistency) across technical applications.  This is in the mark of a true open-environment combative methodology (simplifying responses as much as able due to the endless complexity of the environment), as opposed to elaborating on simple methods under controlled and regulated circumstances or for each new situation – which is the mark of combat sport and training untethered from practical considerations.

Keeley includes mindset in his discussion of Integration as well, noting the concept promoted by the International Hoplology Society (of which Keeley is/was a board member):

“One Mind, Any Weapon.”

Mindset does not change based on combative platform. Such consistency may be hard to conceptualize for some, perhaps wondering how it is they should grapple with the same mindset and the same body as when they use a knife, or a Glock pistol,  but through proper integrated training, such confusion usually disappears. As combat conditioning and combative applications tend to go hand in glove as well, an apt phrase for the adaptive, interdisciplinary tactician, would be:

One Mind,

One Body,

Any Weapon



(1) Keeley, Liam; The Tojutsu of the Tatsumi-Ryu, Murphys Law, and the K.I.S.S. Principle, in Sword and Spirit, Classical Warrior Traditions of Japan Volume 2. Edited by Diane Skoss.


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