Also, "Gakun," page 58-59 of Dennis Palumbo, Techniques of Sandan GI: The Essence of Hakkoryu Jujutsu, Paladin Press, 1993.
Also "Shihonage" and "Yonkyo," Sam Combes, Aiki-do, Volume 1, Black Belt Video, 1999.
Also "Ude Guruma Ushiro" (technique 1-11), which is a shihonage takedown from George Kirby, Black Belt Budoshin Jujitsu, Volume 1, Panther Productions, 1992.
Also, "Shihonage," page 71-81, "Yonkajo," page 118-123, Gozo Shioda, Total Aikido: The Master Course, Kodansha, 1996.
Also, "Yonkyo," page 198-203, "Shihonage," page 206-215 of A. Westbrook and O. Ratti, Aikido and the Dynamic Sphere: An Illustrated Introduction, Tuttle, 1970.
Step 13 of H. Godan is the move after the first kiai, when we turn anti-clockwise into side stance and do a gedan barai to the south.
The critical question here is whether we want to turn anti-clockwise (like Shotokan) or clockwise (like Seito Shorin Ryu). (See the "perspective" article for more information.)
- Clockwise: This leads to a shihonage (nihonage) throw. This is a beginner technique in most branches of jujutsu and aikido.
- Anti-clockwise: This leads to a gakun (yonkajo) takedown. This is an expert technique that is difficult for beginners to perform.
Either throw will drop the enemy on his back, directly on the hilt of the knife that we left protruding from his back in the previous cluster.
Shihonage (Nihonage)
Shihonage is the "four-direction throw" of aikido. Nihonage, the "two-direction throw," is the same technique in Hakkoryu jujutsu. The significance of the name is that you can "aim" the opponent at the person you want him to hit when he falls. The throw is not very damaging to uke unless you aim him at the legs of another enemy, or maybe at a fire hydrant.
In step 12 you shoved the attacker's knife into his right kidney (with a kiai). You still have a grip on his right hand at the beginning of step 13. Bring your left foot up to your right, raise your hand high in the air, and pivot to your right. Allow his arm to pass over your head as you turn. Face south. You have his right arm twisted up next to his ear in the classic shihonage setup. Step to the south with your right foot and do the "downblock" gesture. The opponent drops on his back (on the hilt of the knife).
You can let go of him. He's done. The knife twisting in the wound will do incalculable damage.
Gakun (Yonkajo) Nage
Gakun means "effective grip." It is a major feature of Hakkoryu jujutsu, and is used to a lesser extent in aikido, where it is known as yonkajo, the fourth basic control technique.
Gakun looks completely harmless when viewed by a third party. There is a hard, bony spot on the underside of your index finger knuckle. When you loosely grasp a person's forearm with your hand, this bony spot can be pressed into nerves and tendons of the forearm, causing amazing pain. A person practiced in gakun techniques can casually push your forearm downward, and your knees will buckle in pain. He can also rotate your arm back and up behind you, and use gakun pressure to drop you on your back. This technique looks very much like step 13 of H. Godan. The exact technique is illustrated on page 118-119 of Total Aikido by Gozo Shioda.
With a grip on the opponent's right wrist (after the kidney stab in step 12), bring your left foot up next to your right. Rotate anti-clockwise, like the kata, pushing his arm ahead of you so that it rotates up behind his back. His elbow will point upward, which is a signature posture for this technique. Step strongly to the south with your right leg; use the power of your body to drive the gakun grip to the south and down. The opponent will spill on his back, landing on the hilt of the knife. That will finish him.
Gakun is difficult to learn to do, so teach shihonage to the beginners and save gakun for the black belts.