I haven't fully appreciated this kata until recently. When I started to get a good feel for the hip action, this kata truly became alive for me.
Practice this kata both directions, starting to the left, and doing a mirror image starting to the right. There are some movements that are only expressed on one side of the body, and while in class you will be training this in the formal manner, in your self training, work it to both sides of the body.
The hip action in the first block to the left is fairly classical. This can be seen as just a pushing sort of block. However, to make this stronger, visualize this as a block strong enough to break your opponent's arm. This will drive a much stronger hip action. Get low and then extend out.
The second movement is challenging as you step up for the double block as your hip has a small area within which to create power. The step helps. This is a breaking move; it must be strong and sharp. The same for the next double block.
The next three movements are the same, but to the other side. Remember to drop your body down after the double blocks have raised you up.
Going down the floor, the reinforced block feels so good when done with the correct hip timing. The hips must move sharply into position. The step forward spearhand must have a strong rear leg and hip action. The turn and strike provides many opportunities to let the hips fall out of line; keep them tucked under tight and practice this movement slowly over and over. The final step and punch has similar hip and leg action as the spearhand. Note that these four movements comprise changing of stances as you move all of which create different hip action to start the move. You must practice this diligently, while at the same time practicing moving in only front stance like in Heian Shodan, in order to build the correct abductor and adductor muscles. Practice going forward and back, slow and fast. This is a perfect training tool for creating body movement necessary in emergency situations.
The turn and stand, like the turn and strike, must be done with the hips turned under strongly. While the kata calls for doing this slowly, experiment with different applications which might need you to move quickly.
The knee lifts, elbow block, and strike can be very fun. Don't let your hips loose and collapse on the knee lift. This is a strong movement, like you are doing a knee strike on your opponent without the assistance of your hands. Practice on a heavy back to get a good feel. Keeping the hips tucked under will help generate a sharp hip twist for the elbow block. This also generates a strong stomping action which is one of the bunkai for this movement. An extremely sharp hip action back is required for the snapping fist strike. Squeeze the legs hard when moving to the next knee lift; this does wonders for the power of the entire movement.
When you reach out on the slow, sweeping block, take that opportunity to tuck the hips in hard. Notice a pattern here? :). The stepping punch is fairly traditional, like the others.
The turn and elbow strike, then slide and elbow strike, are very challenging for me. Again, the hips have little room to move and generating power is challenging. In a real situation, if someone does have a hold of you from behind, he has a good opportunity to throw you to the ground. Keep the side stance strong and create a strong fixture, if you will, by having a strong connection in the joints from the floor up to the shoulders. Your strike will be more powerful and you'll stand a better chance of keeping your feet.
I really love this kata. While the kata seems very basic to look at, it contains a great amount of tools for varied body movement which enables success in the critical factor of distancing.
Finish with Heian Shodan and dojo kun.