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Kenjiro Hori, PhD
JKA WF England
“Jiku-ashi / 軸足”
“空手は床を使う者が強い / Karate wa yuka wo tsukau mono ga tsuyoi”
“In karate, those who use the floor are the strong ones.”
I had the pleasure of translating for Imamura Sensei some years ago at an international course. The above sentence was something that I translated, which probably did not get noticed by most of those who were present. For me, though, I have been thinking about it ever since: how do I use the floor to make my karate “tsuyoi karate” (strong karate). In my journey with this, I have realised that a strong jiku-ashi is a key to being able to use the floor. In this essay, I would therefore like to focus on this point – the importance of jiku-ashi.
Using all of the foot
Before I go through different techniques, it is essential for me to first stress the importance of the foot, or more specifically, the sole of the foot (ashi-no-ura) in jiku-ashi. Many years ago at another international gasshuku, Ueki Shuseki Shikan informed us that referees at World Championships pay attention to the back-foot in zenkutsu-dachi, checking whether the outer edge is lifted up or not. Shuseki Shihan stressed that the whole of the sole of the foot must be touching the floor. I teach my students that this principle also applies to jiku-ashi; whether one is stepping forward with an oi-zuki or a mae-geri, or doing a keage in count 6 in Heian Yondan, the whole of the sole of the foot of the jiku-ashi must be in contact with the floor. Shimizu Sensei once helpfully explained this in a Zoom session that we must have all following three points of the foot pressed to the floor: the bottom of the big toe, the bottom of the little toe and the heel. This enables one to apply maximum pressure on the floor, which, as an application of the “law of action-reaction”, in turn generates maximum power in techniques.
Choku-zuki
First then consider choku-zuki in shizentai. Naka Sensei often demonstrates the importance of jiku-ashi in choku-zuki by asking a volunteer to stand on one leg and punch. He first asks the volunteer to stand on the right leg and have the left knee up (i.e. the right leg is the jiku-asahi), and do a left tsuki. When Sensei slaps the left fist from the front the volunteer is unstable. Sensei then asks the volunteer to punch with the right; this time the volunteer is able to stand solid and the punch is strong. Naka Sensei’s explanation for this is that when doing a choku-zuki, the leg that is the same side as the tsuki is the jiku-ashi in the technique.
One of the exercises that Shimizu Sensei often asks us to do is choku-zuki in shizentai but with yori-ashi to the side, where the tsuki hand is the same side as the direction of yori-ashi. For example if the slide is to the right, the tsuki is with the right hand. As the heel of the leading foot (the right foot in this case) presses the floor, it generates the reaction power off the floor, through the right leg, via the right hip, onto the right tsuki, making it strong. This exercise therefore again emphasises the use of the right leg (i.e. the leg on the same side as the tsuki) as the jiku-ashi for choku-zuki.
Mae-geri
I have been very fortunate in being asked to translate for Imamura Sensei on many occasions. One point that Sensei often emphasises is the fact that mae-geri is not all about the kicking foot, but that the kicker must press down on the jiku-ashi as they kick. Sensei explains this by having his hands much like in counts 31/32/33 of kata Enpi, with the right teisho doing the oshi-age and the left teisho doing the oshi-sage if kicking with the right leg, emphasising the opposite forces applied from the tanden to the two feet as you kick. I have demonstrated this to my students by showing them the difference between mae-geri with, and without strong front leg jiku-ashi. Counter-intuitively for many beginners, when I push down on my jiku-ashi I am able to have all my body-weight behind the mae-geri, making the keri much heavier.
Oi-zuki
Kawasoe Sensei has a kuchiguse (habitual phrases), which is “Down, down!”. Sensei says this while doing an oshi-sage with his hand in front of his tanden. In his sessions this is applied to every technique, from choku-zuki to age-uke to ushiro-geri (more on this later). In the most recent course that I attended with Kawasoe Sensei, he emphasised that in oi-zuki too, one must press down on the front foot as you step forward. When I take this back to my dojo, I explain to my students that it is again about the jiku-ashi; at the half way point when the feet are level, the leg that will become the back leg in zenkutsudachi must be understood to be the jiku-ashi. This leg must be pressed down, allowing it to then push forward from its heel to generate maximum power in the oi-zuki. During this move again all of the sole of the foot must be in contact with the floor, in a perfect demonstration of how to “yuka wo tsukau” (use the floor). This is excellently demonstrated in the video of the most recent Honbu Gasshuku in Autumn 2023, in which Shimizu Sensei explains that, on contrary to what many people focus on when stepping forward, which is the front foot, stepping is actually controlled by the back leg, the jiku-ashi. The jiku-ashi first pulls the body forward by contracting the inner thigh muscles. The jiku-ashi then pushes the body forward, this time by expanding (or in Shimizu Sensei’s case, exploding!) the inner thigh muscles.
Stepping back
Stepping back is not easy. Students often start by kicking the floor with their front foot, then proceed in stepping back with their body leaning forward and their hip sticking out at the back. I have heard different helpful tips to correct this. Many years ago, one of the Honbu Dojo instructors told us that we should focus on the back of the head. When I tell students this, it results in a remarkable improvement in their posture. More recently, I have had Naka
Sensei’s teaching to use Chu-Tanden to initiate stepping back. I have been practising this and it works amazingly. Either way, beginners (and more senior practitioners too!) find stepping back difficult as they struggle to transfer weight from their front leg to back leg (hence the front foot kicking and the bad posture). My tip for my students is to keep the hip joints soft so that they can immediately form a jiku-ashi with the back leg. The jiku-ashi then controls the stepping back, first to the half-way point (again by contracting the inner thigh muscles), and then in pushing back of the back leg heel. The focus on the jiku-ashi also makes the power of any blocks (e.g. an age-uke) to go forward even when stepping back.
Turns
I find that many of my students, even at brown or black belts, take the 270 degree turn in count 9 of Taikyoku Shodan, or count 18 in Heian Shodan, too cautiously. They explain to me that this is because they are nervous of wobbling as they land. Of course I say to them that unless they train with full speed and power, and master not to wobble, then they will not get better. However I also teach them how to use the jiku-ashi to improve the turns. For me I have found it best to first push into the front knee as I begin the turn, so that the hip joint is directly above the front foot heel. This creates a vertical jiku around which I spin, at the same time pushing forward from the jiku-ashi heel to complete the turn (again “exploding” the inner thighs). This makes the turn much sharper and stronger. I am aware that this is not the same as what Naka Sensei teaches, where he uses the principle of fuantei (unbalance). However, of course lower grades must first learn to turn on a vertical jiku before they can start attempting Naka Sensei’s advanced way. Additionally, I interpret the fuantei turn as still turning on a jiku, but the jiku is no longer vertical but tilted in the direction of the technique. Perfecting this is therefore only possible if one learns to form jiku properly, whether vertical or tilted.
Ushiro-geri
A very common mistake in ushiro-geri is to pull the weight back before spinning. In doing so, the kicker forms a hizakutsu stance facing away from the opponent, before kicking backwards with the front leg of hizakutsu. This may make the kick stable, but obviously slower. Instead the body weight should always be moving towards the opponent from the start of the kick. As with the turns above, this means that the kick is initiated by pushing forward into the front knee, again creating a vertical jiku. A quick spin of the hip around this jiku bringing the heel of the kicking foot to the jiku-ashi knee, and then extending it for the keri makes the ushiro-geri very difficult to block.
Training Jiku-ashi
In my dojo, in every session I make my students stand on one leg and lift their knee to the front in the mae-geri hiki-ashi position. New students wobble. I tell them to bend their standing leg ankle, knee and hip joint and “drop their inside” (the core). I also tell them to have all of their sole of the foot flat on the floor. Then without dropping the front foot, I tell them to bring that foot to the nami-ashi position (keage hiki-ashi), then to the side (mawashi-geri hiki-ashi), then to the back (stretching of the quadriceps), and finally to the front again, all the time keeping their balance. Initially I was doing this for students to learn
the hiki-ashi positions while stretching their hip joints. After a while though, I realised that it is also training them to form a strong jiku-ashi, by the correct use of the foot, the joints and the weight distribution. I have seen improvements in their stances and techniques, which I believe is a result of this exercise.
Another exercise that I often do is to use Taikyoku Shodan. For each step I point out the jiku-ashi leg so that students can focus on the use of that leg rather than the blocking or the punching hand. So for count 1, I shout “right leg”. Then for count 2, “left leg”. Count 3 is “left leg”, count 4 is “right leg”, and so on. Of course this can be applied to all katas: “right leg” for the first move of Jion, “left leg” for the first move of Nijushiho. Particularly difficult is the “left leg” for the first move of Gojushiho-sho. Kobayashi Sensei explained at the Honbu Gasshuku in Spring 2023 that the reason why JKA teaches “te-ashi-doji” (hand and feet together) in slow moves of katas is because slow moves are meant to be fast moves performed slowly. For example, if you are stepping in to prevent the opponent from grabbing your collar with kakiwake (count 2 of Jion), it would be too late to first step and then do the kakiwake. Instead, they need to be executed simultaneously. Applying this to count 1 of Gojushiho-sho with hidari zenwan suihei kamae and migi uraken jodan mawashi uchi requires an extremely strong left jiku-ashi!
Concluding remarks
Jiku-ashi is one of the ongoing research topics for myself and my dojo. As I remarked at the start of the essay, it is a part of my long-term pursuit of “tsuyoi karate”. I ask my students what the biggest object in the world is. Of course it is “the earth”. So I tell them to have the earth behind their techniques, i.e. “yuka wo tsukau”. However the reaction force from the floor is wasted without a jiku-ashi; only through a proper use of jiku-ashi that the force is transferred to the techniques, as described in this essay above. I strive to continue my research in this.
Cambridge Karate Dojo 