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arxiv: 1907.01220 · v1 · pith:OLUAWRENnew · submitted 2019-07-02 · ⚛️ physics.pop-ph

The increasing importance of Ashi Waza, in high level competition. (Their Biomechanics, and small changes in the form)

Attilio Sacripanti This is my paper

Pith reviewed 2026-05-25 10:50 UTC · model grok-4.3

classification ⚛️ physics.pop-ph
keywords judoashi wazabiomechanicsko wazafoot sweepscompetition formkodokan techniques
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The pith

Ko Waza Ashi Waza throws share one biomechanical principle and basic movements despite distinct names.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper examines the biomechanics of six specific Ko Waza foot techniques in judo and finds that they rest on the same physical principle of leg sweeping and unbalancing. It also tracks small adjustments to the classic Kodokan forms that first appeared in competition and have since become the standard execution used by national federations and inside Japan. A sympathetic reader would care because this unification shows why Ashi Waza have grown more common at the highest levels and suggests training can concentrate on one core action rather than six separate drills.

Core claim

Although Japanese followers consider the Ko Uchi Gari, Ko Soto Gari, Ko Uchi Barai, Ko Soto Barai, Ko Soto Gake, and Ko Uchi Gake as different throwing techniques, from the biomechanical point of view all these Kodokan throws are based on the same physical principle and practically on the same movements. The small changes in the applicative form of the techniques, from the basic movement defined by Kodokan, born from practical competitive situations and have become the usual applicative form among National Federations and in Japan itself.

What carries the argument

The single shared physical principle of leg sweeping and opponent unbalancing that underlies all six named Ko Waza techniques.

If this is right

  • Coaches can teach the six techniques as small variations of one base movement rather than as separate skills.
  • Ashi Waza gain importance in high-level competition precisely because the adapted forms fit real match conditions better.
  • National federations and the Kodokan itself now transmit the evolved versions as standard practice.
  • Biomechanical study of other judo groups could reveal similar unification of apparently distinct throws.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Simplifying instruction around one core sweep could reduce training time while maintaining effectiveness across different federations.
  • The same pattern of competitive drift may appear in other throwing families once video databases are examined systematically.
  • Rule changes that reward foot techniques would further amplify the value of these adapted forms.

Load-bearing premise

The observed small changes in how the throws are performed originated in competitive situations and have now replaced the original Kodokan execution as the usual form.

What would settle it

High-speed video of recent world or Olympic matches that either shows athletes consistently using the modified competitive forms or shows continued use of the strict Kodokan execution without those adjustments.

read the original abstract

In this paper we are interested, both: at the description of Biomechanics of the Ashi Waza techniques, with precision of few of them, members of the Japanese, so called, Ko Waza group; and at the biomechanical analysis of the small changes in the applicative form of them. These small changes, from the basic movement defined by Kodokan and show in thousand books, probably born from practical competitive situations. They are today become the usual applicative form, not only present among the various National Federations, but also in Japan itself among Universities dojos and the Kodokan. Among the Ko Waza techniques, we will select for our analysis only the following: Ko Uchi Gari , Ko Soto Gari, Ko Uchi Barai, Ko Soto Barai, Ko Soto Gake , Ko Uchi Gake That are considered by Japanese followers different throwing techniques, as the different names show us. But from the Biomechanical point of view all these Kodokan throws are based on the same physical principle and practically on the same movements.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 1 minor

Summary. The paper describes the biomechanics of Ashi Waza (foot) techniques in judo, with focus on six Ko Waza throws (Ko Uchi Gari, Ko Soto Gari, Ko Uchi Barai, Ko Soto Barai, Ko Soto Gake, Ko Uchi Gake). It asserts that, despite distinct names and traditional classification as separate techniques, these throws share the same underlying physical principle and involve essentially identical movements, with observed small form variations arising from competitive practice and now standard in high-level judo including in Japan.

Significance. A substantiated demonstration of biomechanical equivalence across these techniques could unify training approaches and clarify technique evolution in competition. The manuscript correctly identifies a potentially useful observation about form convergence but does not supply the quantitative support needed to elevate the claim beyond qualitative assertion.

major comments (1)
  1. [Abstract] Abstract: the claim that the six named throws 'are based on the same physical principle and practically on the same movements' is presented without any equations, force or torque diagrams, kinematic trajectories, ground-reaction force data, joint-angle comparisons, or side-by-side analysis showing that named differences are kinematically negligible.
minor comments (1)
  1. The abstract and title contain awkward phrasing ('at the description', 'show in thousand books') that reduces readability; minor copy-editing would improve accessibility.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their constructive comments on our manuscript. We address the major comment point by point below and indicate where revisions will be made.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the claim that the six named throws 'are based on the same physical principle and practically on the same movements' is presented without any equations, force or torque diagrams, kinematic trajectories, ground-reaction force data, joint-angle comparisons, or side-by-side analysis showing that named differences are kinematically negligible.

    Authors: We agree that the abstract states the biomechanical equivalence without quantitative supporting elements such as equations, diagrams, or kinematic data. The manuscript offers a qualitative analysis grounded in the shared mechanical principles (e.g., application of torque to disrupt balance via foot sweeps) and observed movement patterns across the six Ko Waza techniques, drawing from standard Kodokan descriptions and competitive adaptations. As this is a physics.pop-ph submission focused on conceptual insight rather than experimental measurement, no new force-plate or motion-capture data were collected. We will revise the abstract and introduction to qualify the claim explicitly as a qualitative biomechanical equivalence based on shared principles and general movement structure, while noting that rigorous kinematic validation would require additional quantitative studies beyond the scope of this work. revision: yes

Circularity Check

0 steps flagged

No significant circularity in derivation chain

full rationale

The paper asserts that six named Ko Waza techniques share one physical principle and essentially identical movements, but this is presented as a direct biomechanical observation rather than the output of any derivation, equation, or fitted parameter. No equations, self-citations, uniqueness theorems, or ansatzes appear in the supplied text, and the selection of techniques is not shown to be defined by the sameness claim itself in a way that reduces the result to the input by construction. The qualitative grouping therefore stands as an independent (if unsubstantiated) statement, not a circular reduction.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

No free parameters, axioms, or invented entities are stated or required by the abstract.

pith-pipeline@v0.9.0 · 5722 in / 1067 out tokens · 24871 ms · 2026-05-25T10:50:39.381343+00:00 · methodology

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Reference graph

Works this paper leans on

19 extracted references · 19 canonical work pages

  1. [1]

    Updating Technical Information

    work page

  2. [2]

    Basic Biomechanics of leg movement in Ko Uchi - Ko soto

    work page

  3. [3]

    2 Attilio Sacripanti EJU Scientific Commission The increasing importance of Ashi Waza, in high level competition

    References. 2 Attilio Sacripanti EJU Scientific Commission The increasing importance of Ashi Waza, in high level competition. (Their Biomechanics, and small changes in the form)

    work page

  4. [4]

    Ko-uchi-gari [minor inner reaping throw] is a versatile throw of which the exact origin is unknown

    Introduction In this paper we are interested, both: at the description of Biomechanics of the Ashi Waza techniques, with precision of few of them, members of the Japanese, so called, Ko Waza group; and at the biomechanical analysis of the small changes in the applicative form of them. These small changes, from the basic movement defined by Kodokan and sho...

    work page

  5. [5]

    See Tab 1,2,3,4, in both functions as winning techniques and /or most used

    Updating Technical information In these last times, in high level competition, the use of Ashi Waza is increased, probably due to the new referee regulations. See Tab 1,2,3,4, in both functions as winning techniques and /or most used. Rio Olympic 2016 Winning Nage Waza (Female) Te Waza 15 20% Ashi Waza 32 42% (25%)* Koshi Waza 16 22% Ma sutemi 1 0,01% Yok...

    work page 2016

  6. [6]

    attracts

    Basic Biomechanics of leg movement in Ko Uchi - Ko soto In term of Biomechanics the group of techniques described before in picture, can be seen as the same application of the Couple applied by Tori by Arms and one leg [6 ], starting in two parallel planes to his transverse plane and continuing along the trajectory defined by the rotation of Uke’s body ar...

    work page

  7. [7]

    It is a random function of time with zero mean and a covariance proportional to the Kinetic energy produced, in our case.” athletes fight”, by the work of push-pull forces

    [7] s d L dL TLdt I dt  = = = − The solutions are easily evaluated: ( ) ( ) 0 00 0 ( ) [8] ( ) (1 ) [9] ( ) [10] ( ) [11] t t ss s L t L e t t L e II the stationary solutions t are L t T Ttt I          − − =  + −  = + + −  −     + As well known, to account for the sharp distribution in mechanical terms, Langevin added to the...

    work page

  8. [8]

    [7] s dL dt I dL TLdt   = = −  Because in our situation T and μ are independent of position the Hamilton equations [7] and [8] are recovered on average. Then the Newtonian approach is connected to the average on long time and space, while the Brownian motion characterizes very short time and microscopic space of observation In the mechanical model of ...

    work page

  9. [9]

    [16] and [17] yields the velocity of the Tori’s foot

    Solution of Eqs. [16] and [17] yields the velocity of the Tori’s foot. 7 ( )1 2MMV gh M + [18] From this result we can evaluate the formula of the effective impact force, whose variability is linked to the contact speed divided by the square root of the double height ( ) ( )11( ) 2 ( ) 2dV d d dxF M M M g h M M g hdt dt dx dt=  +  + [19] Whit simple ca...

    work page

  10. [10]

    Couple applied by Arm(s) and Leg

    Minor Changes Today as already previously indicated around the world and in the Japan too little changes are introduced into the Kodokan form, these variations probably born from competitive application are , for some people, they seemed more effective, or more suited to their morphological structure, so much so that in Japan for example Nakamura Yukimasa...

    work page

  11. [11]

    Conclusion In this short paper it is shown the biomechanical models of Ko Uchi, Ko Soto , throwing techniques, that are increasing in importance, because of their effectiveness in competition, so as to increase their presence as winning techniques in international competitions. All these techniques are classified in the Couple group with a Couple applied ...

    work page

  12. [12]

    Gustavo Silva “Results Book Rio 2016 Judo 6-12 August “Ver.1.1, Rio 2016 Organising Committee for the Olympic and Paralympic Games rio2016.com

    work page 2016

  13. [13]

    IDO MOVEMENT FOR CULTURE. Journal of Martial Arts Anthropology

    Fabio Pereira Martin and Coworkers “Techniques utilised at 2017 Judo World Championship and their classification: comparisons between sexes, weight categories, winners and non- winners. “IDO MOVEMENT FOR CULTURE. Journal of Martial Arts Anthropology”, Vol. 19, no. 1 (2019), pp. 58

    work page 2017

  14. [14]

    Personal Communication

    IJF “ Personal Communication” 03/18/2019

    work page 2019

  15. [15]

    Dynamic Judo Throwing Techniques

    Kazuzo Kudo “Dynamic Judo Throwing Techniques” Japan Publication Trading Company 1966 [5[ de Creé, Edmonds “ A technical-pedagogical and historical reflection on the conceptual and biomechanical properties of Ko¯do¯kan, ju¯ do¯’s “ko- uchi-gari” [minor inner reaping throw] “ Comprehensive Psychology , (2012), Volume 1,

    work page 1966

  16. [16]

    Gittermann The Chaotic Pendulum World Scientific 2010 ISBN 13 978-981-4322-00-3

    work page 2010

  17. [17]

    Modern evolution on ancient roots

    Sacripanti A: Advances in judo biomechanics research. Modern evolution on ancient roots. Saarbrücken, Germany: VDM Verlag Dr. Müller Aktiengesellschaft & Co. KG.; 2010. ISBN-13 978-36391054

    work page 2010

  18. [18]

    Yoshitaka, Y., JUDO waza no daihyakka ( Encyclopedia of JUDO techniques) (in Japanese). Vol. 2 Baseball Magazine sha,. (2015) ISBN978-4-583- 10821-6

    work page 2015

  19. [19]

    Youtube An Cang rim 3 types of Ko Uchi Gari he uses., https://www.youtube.com/watch?v=OXZMxsTmqS4

    work page