Differences in Isshinryu and some most styles
Most all Karate styles are very similar in techniques and in execution of techniques.
There are a few differences in Isshinryu and other styles of Karate
The most noticeable of these differences is the Isshinryu fist
FIST: The fist is made tightly with the thumb on top and not held on the side of the fist. This minimizes the chance of catching the thumb in an opponents Gi or clothing. The thumb can be used in a striking manner to a soft target like the temples. Most open hand techniques the thumb is tight against the hand, in Isshinryu the thumb is in the correct position when the hand opens and does not need to be moved.
PUNCH: The Isshinryu punch is to the center chest, lower sternum instead of the solar plexus as in many styles. With proper power, this is considered a primary target. The exception to this would be children.
The arm does not turn when punching and the arm never locks out. The arm always returns to a guard position.
With the primary target being the sternum. The vertical fist penetrates the target area easier. Imagine if you had a large attacker with big pectoral muscles. If you turn your fist, the impact can be absorbed by the muscles. When the fist is held vertical. The knuckles impact the sternum allowing maximum penetration.
Turning the arm to strike with the fist horizontal. To an Isshinryu practitioner it makes very little sense to turn your arm in a position, where the elbow rotates to the outside of the body. This puts you in a very dangerous position. If your opponent can grab or even slightly hook your arm at the wrist end. It takes very little effort to convert that into an arm bar or break, by impacting the elbow. A move which has been called an Okinawan Sheer.
The arm always comes back to a guard. One of the beautiful things about Isshinryu is that is a no nonsense functional style. Regardless how nice it might look to leave the arm extended in kata. When would you ever do that in an actual conflict. You may need the guard, you may want to punch a second time. More importantly to leave a limb be it an arm or a leg. Extended toward an opponent, puts you at risk. Imagine leaving an arm extended against someone who studies Ju Jitsu, Mixed Martial Arts or is a Judo Player.
Blocks: All Basic Isshinryu blocks make contact with the lower part of the arm. The arm is in a position where both bones of the arm contact the target at the same time. Not just the little finger side of the arm. This not only adds power to the block, it protects the blocking arm. By aligning the arm so that both bones strike at the same time, it reduces the chance that one of the bones could be broken. These are very aggressive blocks executed with the goal of slowing the attacker. Blocking in this manner with only the outside (Little finger side) of the arm is considered to be dangerous to the blocker. Since it increases the chance of breaking your own arm.
Stance: There is no stance in Isshinryu with a locked leg. The knees are always kept bent and flexed, to protect the joints.
Kicks: Kicks should not be locked out. With snap kicks, roundhouse which snap from the knee. This is an easy concept. The foot is withdrawn quickly. With Thrust kicks during drills, we sometimes leave them momentarily extended, however it is rare that you would extend and lock a leg in a sparring situation.
Roundhouse Kick and Snap kick: Striking with the ball of the foot verses instep. Technically there are no instep kicks in Isshinryu. Reaching in with the ball of the foot gives better penetration and if the leg is blocked, it can even give a little more range then an instep. However practically speaking, with the advent of sparring pads and the fact that in a self defense situation we would in all probability be wearing shoes. There is a place for instep kicks, even in Isshinryu.
