Ashi Sabaki or Unsoku – footwork
Footwork in karate is considered an operational technique, since its purpose is to shift for distance or/and to produce momentum force to the technique, it allows us to be in the right time in the right space. Its purpose is to allow us to apply the necessary technique, avoid attack or for strategy.
Footwork or shifting should be smooth, sharp, without back motion. We say that the footwork should be hidden, so as the feet move underneath the body and the torso should not show any change.
Traditionally, the kata do not emphasize foot work, and so is karate as practiced in Okinawa, there was emphasize on using the stance, but not smooth shifting.
Mostly, our footwork training comes from Japanese Budo, as karate came to Japan and kumite training became more integral part of training, footwork training was emphasized more. Any strong technique is useless if it cannot be applied in proper timing and distance.
The stance while moving with the opponent is different than the stance of technique execution, it should be higher, almost like natural everyday life walking, so it is easy to control the legs from the core muscles, and we are more mobile.
At impact we prefer a deeper stance for strong base to deliver force from.
Whenever we react to the opponent the breath and feet should move first, never the extremities or top technique, even when we react in place, it’s the breath and feet that initiate ground reaction and technique as a chain from the ground up.
Ukimi- suspension, floating
While shifting, the body center should suspend the legs; it should feel as if the legs are hanging from the body center and are free.
The muscles of the pelvic floor, lower abdominals, buttocks and inner thighs should be active in suspending the legs; it should feel as if those muscles are drawing the legs gently into the body’s center.
It should feel as if there is no weight on the feet, yet the toes should have a strong feel in them, which help connecting the abdominals and feet.
Try to feel extension through the spine all the way through the cervical spine, which help keeping all the joints free.
The breath has to be from the abdomen, if the breath is from the chest, it is impossible for the body center to control the legs.
Zui Ban- accompany movement
The body center moves and the legs cooperate, the legs movement is function of the center and spine, so the legs (hip, knee and ankle joints are free) are soft and do not make isolated effort (to be able to apply accompany movement, the concept of ukimi has to be build in the nervous system, and the legs have to have a slight squeeze to each other, so the legs work as a unit with each other and with the body center).
The body center is the base from which the legs are moving from, it has to be stable and moves only as much as it needs to.
Sometimes, Sensei Nishiyama goes so far as saying to move only from internal force (the body center), not to worry about using the legs and ground reaction, and the purpose of this is so one does not over use the legs, making a back motion. This is OK providing one has already established the best angles between legs to torso and to ground, and the breath connects to back leg, and is proficient enough, so he will use the ground following these instructions, but not overuse.
Good indication of someone overusing the legs is stamping the floor and loud footwork; the feet should glide on the ground, as if there is no weight on the feet.
One should feel as if walking on thin ice without breaking it.
Body weight between feet-
Because the pressure can be applied to either foot by using the breath, to produce ground reaction force, if the weight shift over one leg, then we are more likely to float, and even if we could apply pressure to floor, the angle of the ground reaction force is not to the line of the technique.
Itsuku – being glued, stuck, stiff
This is obviously a condition to avoid; the legs get stiff, heavy, and not responsive. Usually when we judge too hard, when the breath stops or rises. Even when we are not moving the breath has to interact with the feet, and there must be potential energy.
Types of shifting-
Yori ashi (slide) or Okuri (send) Ashi
This is the most common shifting method, and quickest for short space, but relatively not as smooth as Ayumi or Sugi Ashi.
Using the concept of Zui Ban, front foot moves first (controlled from body center by breath), then body center, then technique, one after another – all together.
The reason we move the foot first and not the body center is that it take more energy, meaning more time to move more mass like the body center.
At the end everything stops and focuses together, only the sequence is important to make more a quicker start and acceleration.
In reality, the body center moves first and the leg and foot extends the center, only that relatively in space the foot is faster, the movement of the sacrum and thigh bone, shin bone and foot have to match.
We say that front foot moves and than back foot push, rather than back leg push in order to move, since that might result in back motion.
The back foot pushes only for an instant and immediately follows and stays united with the body and front foot. The moment the front foot touches the floor and receives pressure by the breath and momentum, there is reaction to the back foot. Pressure returns to back foot, which supports the present technique and produce potential energy, loading for the next technique.
If the back foot drags behind, it becomes an obstacle, like an anchor that pulls opposite direction of the technique, there is no loading, and there is stress on many joints throughout the kinetic chain.
Ayumi Ashi- walking
This is a way to get quickly and smoothly into the opponent’s space, it should feel as if riding on wind.
Using the concept of Zui Ban, the center moves and the legs accompany, feel as if the legs hanging freely from the center.
Differently than regular walking, the toes lead and touch the floor first, rather than the heels, since it is faster.
The knees are slightly bent and the stance is not too deep, like in natural stance, Sensei Nishiyama says to think as if you are sneaking in.
At any instant either foot can apply pressure to ground to initiate a technique.
When walking into opponent’s space, estimate before moving in, once moving in don’t hesitate or stop, your footwork should never stop until catching the opponent, you might attack directly, or switch rhythm with breath and feet, or use sasoi, invite by fake, or switch feet (kae ashi) to catch and mix the opponent’s rhythm, but you should never stop and stall, or hesitate or stop your breath or feet, what we called Itsku (glued, stiff feet).
Sugi Ashi- shuffle
Like chain reaction, the back foot advance, as much as the needed space (sometimes half step, and other times crossing the front foot), and when it touches the ground, reaction goes to the front, advancing foot, the body stays sideway (hanmi) while the back foot advances.
This is a good way to cover more distance smoothly, and it has use many times within combinations or by itself, only it is dangerous to use if the opponent is not off rhythm and behind since while the back foot moves we don’t have good loading. Again the concept of Zui ban is applied
Kae Ashi- switch legs
As the legs are suspended and are hanging from the center, the body center being stable base, moves the legs underneath, the legs are switching to catch the opponent’s rhythm while adjusting the space for a kick or other technique.
The legs can be switched to break and mix up the opponent’s rhythm and once he is behind attack him.
The point is that while the legs are being switched underneath the body, either leg is free to apply pressure to ground (from the center) to initiate technique while adjusting the space or to initiate kick by lever action from the body center.
This means that while the legs are free, the body center can apply two opposing energy direction to either leg, one leg can be lifted from the body center while the other receive pressure to use ground reaction to initiate a technique.
As in any other footwork, the torso should not show any change.
Mawashi Ashi- Circle
Using rotational action from the spine, the legs express this rotation and moves in a circle to avoid the opponent’s line of attack.
The space between the feet should be as small as possible to shorten the moment arm while rotating. When counter attacking it is OK to have a wider space for a strong base at impact and to increase the angular momentum, which makes it easier to decelerate.
When left leg is forward and right foot moves to left this is Kawashi (switch), and is done without shifting the center as possible, when right foot moves to the right, we use the rotation energy to shift the center of mass (it is a more energy efficient way to shift, and more speed can be achieved), but again the shift should be minimal, only enough to avoid the line of attack.
More shifting than necessary means time and we might miss the space that is given while the opponent attacks, but also may give the opponent time and action space for follow attack.
One other way to shift to the right is called Hiraki Ashi (to open the feet), which means to shift the right foot to the right by suspending it from the center, not by rotation, this is less preferable, since it opens us more for the opponent’s continue attack.
When responding to opponent with Mawashi Ashi, Keep your low abdomen close to opponent, as if you dance with him and receive him/her with your stomach, and in line with that, react with your breath and center rather than with your eyes and brain, become the opponent rather than fight him.
Mawashi Ashi can be done while responding with Sen timing, catching the opponent in one timing, while he is attacking, doing Sen while switching (Kawashi) off the line of attack is called Nuke Waza.