Budo the teaching of the Founder of Aikido
Irimi (page 32)
the principle of kokyu (*) timing to enter smoothly to his side;
- be prepared to strike your opponent to the rear with your right hand.
- In an instant, advance deeply to his rear with your left foot, keeping your right foot solidly based,
- and simultaneously cut down with your left hand to his rear.
- Step in with your right foot behind him without breaking your posture and down him with both hands.
- When your right foot is forward the procedure is reversed, and you must answer to your opponents left.
(*) Kokyu: prana, the vital breathy of life, the universal current of vibrant energy.
Technically, kokyu refers to proper timing and a steady, unimpeded flow of power.