My disclaimer: For demonstration purposes I refer to human body parts and how a sword might be used in a battle scenario but this is only for examples, I do not recommend or promote the use of a sword steel or wood on any human beings or animals.
Definition of Waza is technique
Waza One
Vertical Downward Strike
Step 1. Learning the Pattern. Learning Waza 1 first is just to learn the pattern of the strike in this case it is a simple downward movement with the sword. Think of entering the top of the opponent’s head and ending just below belt level. When the blade stops it should be parallel to the ground, about belt level. This is first step of learning the technique.
Step 2. The Arc. When you have become comfortable with that movement, it is time to look at the next step of development.
The arc, as this technique is performed it begins overhead, you should reach out on the strike extending the arm as far forward without compromising the balance. Then begin the strike and pull the sword back to the left chambered position, just as you would do with a punch. Reaching out and pulling back will give movement to the blade. The katana is a slicing type of blade and not a chopper, for a good cut the blade must move across or slice the target. The purpose of each of these steps is to add more movement to the blade.
Step 3. Rising & Dropping. Once you are comfortable with the arc, you will work on the dropping of the body weight with the strike. The strike begins the same as in step one and two but as the technique is performed and the sword begins its downward strike learn to bend the knees, keep the body weight centered and drop. The body will lower and you still pull the sword back to the left chambered position. Dropping the body adds weight to the strike helping the blade cut through pulling back to the chambered position also makes the blade move increasing its efficiency.
The motion of the blade is downward and is being pulled back.
Step 4. More Movement. Adding movement. This is to add movement to the blade as well as the body. Everything is now dropping sword and body, now step back while remaining low. This increases the movement of the sword and moves the body away from the target taking the sword too. To optimize the weapon whether it is a sword, nunchaku or the human body it must move to be efficient, a stationary object does no harm.
The motion of the blade is downward, being pulled back and the now the body moves away from the opponent, distance is created.
Step 5. Deflecting & Striking. This is the toughest one of all because this changes everything you just learned. Think of this technique now as a deflection. This is done in karate too, so it has to be true in sword work, a strike is a block, and a block is a strike. I say block but realize I don’t intend for you to stop the attack but redirect its power, so when I say block it is inter-changeable with deflection. To deflect using this vertical downward movement turn your sword so the cutting edge is to the left and you can use the side of the blade for defense, this way the cutting edge would not be damaged.
Visual your attacker using Waza One against you, you mimic his movement but as a deflection. The point here is to avoid his blade making contact with you so redirect the power down, then you add step 4 his blade goes into the ground and you have moved back to avoid then you could lunge forward with a thrust, finished.
The first time a saw this waza used in a fight was at a NAPMA World Conference. Action Flex was demonstrating the foam sword products. They let attendees battle one of the Action Flex guys each person was armed with a foam sword. The Action Flex guy was also a trained swordsman, I am sure the opponent had some experience as well. On the demonstration mat, the Action Flex guy held his sword over his head in Jodan Kamae, high ready stance. Watching this match I was wondering how his opponent was going to attack and defend against this position. The Action Flex guy will only have to perform a waza one to destroy his opponent. Even though he has left his whole torso exposed there was no way he could be beat.