English Japanese Black Belt Rank Kyu (student) Rank
one ichi shodan ikkyu (Brown Belt)
two ni nidan nikyu (Purple Belt)
three san sandan sankyu (Blue Belt)
four shi/yon yodan yonkyu (Green Belt)
five go godan gokyu (Yellow Belt)
six roku rokudan rokyu (White Belt)
seven shichi/nana shichidan
eight hachi hachidan
nine kyu/ku kudan
ten ju judan

Martial Terms:
block – To stop a strike, usually with an arm (leg blocks also exist). Not the same thing as parry.
godan – Fifth degree black belt.
gokyu – Student rank 5 – AKA “yellow belt”.
hachidan – Eighth degree black belt.
hammerlock – Armlock in which uke’s arm is held behind his back, and pushed as far up the back as tori can get it, thereby applying tortional stress on the shoulder joint. Aiki-style hammerlocks, more common as a tori move in the Zen Budokai charts, are held at the bottom of the back (coccyx) in order to place the uke in an off-balance position to control him more effectively. See police hammerlock.
hanshi – System head.
hiji – Elbow strike.
ikkyu – Student rank 1 (next is black belt) – AKA “first brown”.
judan – Tenth degree black belt.
kudan – Ninth degree black belt.
kuzushi – The concept of “unbalancing”.  In practice, “getting kuzushi” means to take uke off-balance in some fashion, usually by continuing a motion uke has already begun.
military step – In the right-handed version, the left foot is left as a pivot, and the right foot steps to the rear, so that the right foot is behind and at right angles to the left foot. Then the left foot pivots, turning the body 90 degrees. Often used with comealongs.
nidan – Second degree black belt.
nikkyu – Student rank 2 – AKA “second brown/purple belt”.
parry – To redirect a strike, usually with the hand, such that it doesn’t land. Leg parries also exist, but are less common. Not the same thing as block.
rokudan – Sixth degree black belt.
police hammerlock – Hammerlock wherein the arm is held behind the back, pushed as far up as it will go, and the collar or opposite shoulder is held. See hammerlock.
sakotsu – A chop, usually to the neck.
sandan – Third degree black belt.
sankyu – Student rank 3 – AKA “third brown/blue belt”.
shichidan – Seventh degree black belt.
shodan – First degree black belt.
soke – Heir to the system head.
solar plexus – A convergence of nerves that control the diaphram (breathing) and, potentially, heart rhythm. The solar plexus is the nerve bundle affected when one “has the wind knocked out of them”. To affect the solar plexus, strike just below the bottom of the breastbone.
xiphoid process – Small tab of cartilage that terminates the breastbone on the bottom part of the rib cage. This hangs down and is supported only on the top. If struck with sufficient force, it breaks off and may puncture the lungs, liver, spleen, or heart (use with care).
sutemi – Dynamic breakfall. Pronounced “stemi”.
tori – The person who applies a technique (usually the defender). In Zen Budokai charts, techniques are usually initiated by the uke (such as an attack). This sometimes generates confusion – it is easy to reverse these accidentally. See uke.
uke – The person upon whom a technique is applied (usually the attacker). In Zen Budokai charts, techniques are usually initiated by the uke, then tori responds. See tori.
radius – One of the two bones in your forearm (the other is the ulna). The radius is the one that runs on the top of your forearm and ends in a bump just above your thumb.
ulna – One of the two bones in your forearm (the other is the radius). The ulna is the one that forms your elbow and runs to your pinky finger (first metacarpal of the fifth phalange).
yodan – Fourth degree black belt.
yonkyu – Student rank 4 – AKA “green belt”.