What is Rasen-ken (spiral fist)? 螺旋拳とは何ぞや 


First of all, we should define what rasen (螺旋) or spiral is.  In Dictionary.com, spiral is defined as: In Geometry, a plane curve generated by a point moving around a fixed point while constantly receding from or approaching it. This can be found in the natural world such as some shells, plants, bugs and even animals.


In this essay, I wish to share one secret technique of Asai ryu karate with the readers. The fist is called rasen ken (螺旋拳 spiral fist) or in-yo no ken (陰陽の拳 yin yang fist). This fist is being taught in Taiwan among the White Crane kung fu practitioners, but I am not sure if it is being taught in Okinawa. Regardless, I am afraid it is almost forgotten in the traditional karate styles.


Rasen ken or in-yo no ken is consisted of two different styles of a fist. In other words, it has yin-fist and Yo-fist. Yin or In (陰) means moon, shadow or negative. Yo (陽) means sun, bright or positive. With this definition, I am sure the readers will have very little idea what this technique is all about.


This technique is one of the furiken (振り拳) or whip fist techniques. Most of the readers are familiar with uraken (裏拳 photo below left). This technique can be a furiken if it is used with a large and circular arm motion. There is another furiken technique that you are probably familiar, mawashi uchi (photo below right). In short, a furiken technique is defined as a fist whipping technique with a large and circular arm motion. The arm motion can be horizontal but it can be also diagonal or even vertical. The angles and the directions do not matter.



furiken uchi

The important thing is that your arm will swing starting from the shoulder (along with the twisting of the shoulders and the total upper body in many cases).


Furiken techniques, unfortunately are not too popular among the traditional karate styles due to the immense popularity of sport karate. Maybe I do not need to explain as it is very obvious. Most of the furiken techniques will not be able to gain a point in tournament kumite thus they are being ignored or forgotten. On the other hand, these techniques are considered to be one of the key techniques in budo karate including Asai ryu karate.


I assume that now you have a general idea of what furiken techniques are. OK then, let me explain what rasen ken is and how it is used.


Before we go into the explanation, I need to mention something. I needed some photos of a fist demonstrating the technique for this essay. I looked for the appropriate photos, however, unfortunately, I could not find any photos of this nature except one in the public domain. As a result, the photos of the close-up view of a fist used in this essay are the images of my fist.


Yo (sun) fist or Yo-ken (陽拳):

OK, as I have explained earlier there are two separate fists and let us start with Yo ken (sun or positive fist). Look at the two photos shown below. As you can see, yo or yang fist looks very similar to ippon ken. The photo on the left shows the palm side and the one on the right is from the knuckle side of the same fist.


Rasen fist 1Rasen fist 2 2


It is difficult to see the spiral shape in the fist form by looking at these photos. I suggest that you will form one with your own hand.  If you have the fingers lined up correctly, you can see that the second joints of the fingers (but excluding the thumb) are lined up in a beautiful spiral shape. Thought it is important to form your fist this way, forming itself is not the ultimate objective of this fist. Just remember that this form is only a bi-product.


The key point of this fist is that you need to tighten the little finger most securely against the palm, then tighten the other three fingers naturally. The third joint of the index finger will not be bent and you will form an ippon ken. Another key point is the base of the thumb should be pressed against the finger-tips of the middle and ring fingers.


After having rolled in the four fingers, place the thumb on top of the index finger between the first and second joints. The thumb, then presses the index finger down firmly (photo below left: note this photo is used to show the thumb and the index finger, therefore, the thumb base and the middle finger are not forming correctly). The thumb is fully extended and it will line up parallel with the base of the index finger (photo below right).

Rasen fist 4


Rasen fist 5


When you strike there are two methods.  One way is to use the index finger ippon ken where the thumb performs as a support to the ippon ken. The other way is to use the first knuckle of the thumb (Uechi ryu practitioners should be familiar with this method). The key point for both methods is the little finger which must be tightened most firmly.


In (Moon) fist or In-ken (陰拳):

The second fist is In (moon or shadow) fist. Two photos below show the fist from the palm and the knuckle sides. To make this fist, it is important that you must start from Yo (sun) fist that was described in detail above. The key point is that you will keep the fist and you will move only the knuckles to change the fist-forms between Yo and In.

Rasen fist 2

Rasen fist 1-2


Remember that the fingers must be, in general, touching each other all through this process. In other words, do not open the hand or make any space between the fingers during the process. For the In-fist, you will squeeze the thumb tightly against the side of the index finger as seen in the photo (above left). You must tighten the index finger most firmly. Two fingers (middle and ring) are rolled in with the natural firmness but the little finger will be extended at the third joint (photo left).

Rasen fist 7

From these photos I am afraid the spiral form of the fist is still not too visible. Though it is not that important about the fist form, you are welcome to make this fist with your hand if you wish to see a spiral form (provided you have the correct form).


What is important here is to know how to use this fist. With the In-fist, you can hit a target with any of the finger knuckles, however, the little finger knuckle is most frequently used in this fist. To use In-fist with the little finger knuckle, you need to swing your arm in a reverse way. If  you are using your right fist, the right arm will swing clockwise starting from your left chest or shoulder. The movement will be similar to uraken uchi, except the hitting point will be at the second joint of the little finger.


Can this fist be used in a regular circular motion of mawashi uchi (counter clockwise with the right fist)? Yes, it is possible and can be done with In-fist. This fist is not common even among the kung fu styles. Luckily, I could find one photo demonstrating a Japanese Pa Gua practitioner (photo below). As you can see, he is delivering enpi uchi with his right elbow and simultaneously executing a chudan strike with his left In-fist (the opponent on the left side in karate uniform is famous Naka of JKA).Spiral fist_LI (2)


On the other hand, using Yo-fist and hitting with the index or thumb knuckle is much more common in the regular circular motion. Try these fists and see how they work then you can easily see why one way is much easier and also more practical than the other. Now you understand how to make the fists and how to use them individually. That is the first step and now you need to move on to the second step.


What you need to practice is to shift these fists smoothly. However, at least initially, I assume that your knuckles move or fist shifting may be awkward or not smooth. You have to repeat this exercise hundreds of times before it can become natural and smooth. Once, the shifting becomes smooth, it is important that you can do this very quickly. This is because these two fists are often used in the same combination.


The typical combination is as follows. Let’s assume that you are using your right fist. First, the attacking arm will move in a semi-circular movement similar to mawashi zuki in counter clockwise direction. The first impact will be either with the thumb or index knuckle (Yo-fist). Right after the first attack is completed, the arm direction will be reversed (or to clockwise) and hit with the little finger knuckle. For the second impact it must be done with In-fist. If you keep the fist in Yo-fist, it will become kentsui uchi or hammer fist. Of course, that is also an option. However, a hammer fist has a large impact area which means the impact energy will be spread over a large area which results in less impact power. Thus, you want to have a small impact point or a single knuckle. This is why you need to change your fist quickly to In-fist to stick out the little finger knuckle. The arm will swing like a windshield wiper. Between the two hits or impacts, now you can understand why the fist-form must change very quickly.


By practicing these two fist forms of Yo-fist and In-fist, your arms will move if both arms swing more than once, you may be able to swing them in the spiral and possibly vortex motion. Why not include this fist in your repertoire? Try this technique in your kumite training and see if it works for you.  Good luck!


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