by Elie A. Morrell, Shichidan

In recent years the concept of roller and driver throwing actions has been introduced into the judo community. The purpose of this introduction was to attempt to explain in a simple fashion the types of throwing actions normally required to effect the different throwing techniques. If in truth, each throwing technique required a unique throwing action different from all others, then the roller and driver concept would be of no value. It is because most of the throws can be categorized as requiring either a roller or driver type action that credibility can be given to the concept.

In attempting to classify throwing actions in a specific sense, it should be realized that it is a means to an end, and not the end itself. This is because grey areas exist in which the classification of the two actions is not always simple and clear cut. Some techniques arc straight-forward with regard to classification whereas others are not. For example, a throw tike the knee wheel (hiza guruma) can only be done as a roller. The opportunity can vary, however.

The purpose of the concept of roller and driver throwing actions is to indicate that these actions are typical when attempted in the usually accepted form that the throwing techniques take. Variations do occur since the basic throwing techniques can be done in many ways.

Definitions of roller and driver throwing actions will be given in subsequent paragraphs. Before doing this a point of clarification is in order.

A common misconception regarding the roller and throwing actions is that many individuals believe that this ‘type of a throw’ or ‘that type of a throw’ is either a roller or a driver. This is erroneous thinking. Throwing types and throwing actions are not synonymous.

Let us now examine the definitions of roller and driver throwing actions as they relate to both the defender and the attacker.

Roller actions are used when the defender’s feet are usually, but not necessarily, still. The attacker places in the path of the defender (for front or rear throwing) an obstacle such as the arm, leg, hip or body. The head of the defender is typically pulled down (forward throw) and the defender is rolled over the obstacle. The lapel or collar hand is the dominant hand in roller throwing actions.

In accomplishing the roller, the attacker has to get as much of the defender’s center of mass (hip line) close to or contacting his own to effect the required rotation. The attacker needs a very strong tucking action in order to extend the defender’s body curve as far as possible to attain the desired rotation. The tucking action can be achieved by either a direct or indirect method. In the direct method the attacker uses part(s) of his body against part(s) of the defender’s body assisted by his own driving body weight. In the indirect method, the tucking action is achieved by falling body weight with only the attacker’s hands as the common linking points.

In driver actions, the defender is usually in motion at a medium to fast pace. The attacker in this case will drive out one or both of the defender’s legs. The leg(s) are driven out faster than the relative speed of the defender’s upper body. The attacker’s sleeve hand is dominant in driver actions. The attacker will make use of his total body weight to over extend the defender’s movement into the direction of the throw. The driving action in this case is brought about only by the attacker’s body weight.

Irrespective of whether a roller or driver action is used, the attacker’s driving leg must be driving his body weight into the direction of the throw.

Now that the definition of roller and driver throwing actions have been stated we are faced with the problem of practical implementation. When does the attacker use a roller action and when does the attacker use a driver action?

A functional relationship exists between a number of variables when we consider a specific throwing technique. Specifically, these include pace, position of the driving leg, dominant hand and opportunity. The most significant of these four variables is opportunity. A player must know how to relate opportunity to a given throwing technique.

Opportunity as it relates to the attacking movement is defined as the position of the defender’s two feet the instant the throwing action (kake) takes place. Imagine a straight line drawn through the defender’s feet. Driver throwing actions are usually parallel and coincident to this line whereas roller throwing actions are usually at right angles to this line somewhere between the two feet of the defender.

The pace for the roller or driver can vary but should be generally optimized for most throwing techniques. A specific pace should not be considered as being very stringent since individuals will attack with the same technique as a different pace suited to their own temperament. The position of the driving leg is always diametrically opposed to the direction of the throw, or as nearly as possible. The dominant hand has been discussed and is merely a matter of understanding.

Now that we looked at the potpourri of all the variables, let us take the practical approach of fitting everything together by way of some examples. In our first example, we will consider harai goshi as the throw. Right away it is obvious that the attacker drives a leg (by way of a sweep) out from under the defender. Based on our definitions, this technique requires a driver type of action. If the defender’s right thigh is being attacked, this situation normally requires that the opportunity for attack is when the defender’s right leg is forward. This statement is essentially true for the standing throws. Exceptions occur for sutemi waza. However, for our discussion these will not be considered. What now happens if we consider the defender has his right left back at the instant of attack? Is the sweeping action now a driver or a roller type of attack? The attack is a driver action. Needless to say, those with a parochial viewpoint would disagree with this instantly without reflecting long enough to see why it is still a driver. There is no question that there apparently appears to be a conflict of definitions. Careful scrutiny of the definition of a driver action coupled with the fact that it was stated that driver actions are usually accomplished parallel to the line drawn between the defender’s feet should resolve the issue. In other words, if we want to remove grey areas in order to consider all possible locations of the defender’s leg at the instant of attack, all statements cannot be hard and fast. However, our definition of the driver action shall remain firm. That is, the defender’s leg or legs are driven out from underneath him. With these remarks I will introduce what I am calling the variance of opportunity concept.

The foregoing remarks have taken the concept of the driver action and expanded it in context from that which has been understood in the past. In effect, we are now saying that the driver can be utilized for varying situations of opportunity for some of the standing throwing techniques. The same rationale will be used while examining the roller action.

Reflecting back on the definition of a driver and when it is usually attempted we find that maximum effort for forward throws is required by the attacker when the defender’s foot/leg is forward and this effort de- creases as the leg is drawn back until it reaches its position at full rear at which point the attacker’s effort reaches a minimum. The opposite condition occurs when the attacker attempts a throw to the defender’s rear. With this observation we can conclude that opportunity can be said to be independent of the driver action for some throws as long as it is recognized what the interplay is between the action, position of leg and thus the required effort on the part of the attacker!

Let us now examine the roller attacking action. If the defender’s right leg is being attacked then it should usually be to the rear at the instant of kake for some of the forward throws. Consider a throw like koshi guruma. This is a typical roller action conforming to our definition. Let us now apply the same rationale of variance of opportunity as we did with harai goshi. Based on the definition of a roller whereby the defender is said to be virtually stationary, when we consider an attack with the defender’s leg forward the situation becomes a little tenuous. Without any initial momentum of the defender, pulling off a forward throw (roller action) with the leg forward can be extremely difficult. The difficulty arises when the attacker places his right leg outside of the right leg of the defender (assuming a throw to the defender’s right front or direct front). Due to a likely static situation and the method of application of force, typically the defender’s leg gets locked to the mat and throwing can be difficult. Therefore for roller attacks to the defender’s frontal zone it is more expeditious to attack while the right leg is anywhere from a position which equates to a front natural posture to a left natural posture. Successful attacks with the defender in a right posture are just too difficult to accomplish.

In summary, this paper has attempted to simplify to some extent the concept of roller and driver throwing actions. To this end the variable called ‘opportunity’ has been dealt with in a slightly new light. This variable, as indicated earlier is probably the most difficult to appreciate and understand. In no way has the concept of the roller and driver actions been changed. What has been done is to show that opportunity can vary for some of the driver and roller throwing actions without any change in the concept. Thus the introduction of the new term called ‘variance of opportunity.’

The included table presents some selected throwing techniques and their associated type of throwing action usually used to make the throw. Also indicated in the table is a heading labeled ‘Adaptable to variance of opportunity.’ If an affirmative entry is shown in this column it means that the attacker can make the throw with the defender’s leg in any position. If a negative entry is shown it indicates that the attacker is best off if he makes the attack with the defender’s leg in the suggested optimum position, be it either forward or backward. Although the table does not contain a complete list of throws (however that is defined), it does include those most widely used in randori and tournaments. Needless to say, the table would be short if only the popular throws had been included.

The table is based on an attacker gripping with an orthodox grip with the right hand holding the defender’s left lapel and the left hand holding the defender’s right outer sleeve in the vicinity of the elbow.


THROWING
ACTION

THROWING
TECHNIQUE

SUGGESTED POSITION
OF RIGHT LEG

ADAPTABLE TO
VARIANCE OF OPPORTUNITY

R

HIZA GURUMA
SASAE TSURIKOMI ASHI

REAR
REAR

YES
YES

0

UKI GOSHI
SEOI NAGE

REAR
REAR

YES
YES

L

KOSHI GURUMA
TSURIKOMI GOSHI

REAR
REAR

NO
YES, (FEET LEVEL TO REAR)

L

TAI OTOSHI
KO SOTO GAKE

REAR
REAR

YES
NO

E

ASHI GURUMA
TOMOE NAGE

REAR
FRONT

NO
YES

R

0 GURUMA
SUMI GAESHI

REAR
FRONT

NO
YES

S

YOKO GURUMA

FRONT

YES

D


DE ASHI HARAI


FRONT


NO

R

0 SOTO GARI
0 UCHI GARI

REAR
REAR

YES
YES, (FEET LEVEL TO REAR)

I

KO SOTO GARI
KO UCHI GARI

FRONT
FRONT

YES, (FEET LEVEL TO FRONT)
NO

V

OKURI ASHI HARAI
TAI OTOSHI

FRONT OR FEET LEVEL
FRONT

NO
YES

E

HARAI GOSHI
UCHI MATA

FRONT
REAR

YES
NO

R

YOKO OTOSHI
TANI OTOSHI

FRONT
FRONT

NO
NO

S

YOKO GAKE

FRONT

NO


daisho AN INTRODUCTION TO VARIANCE OF OPPORTUNITY FOR ROLLER AND DRIVER THROWING ACTIONS