Shotokan kata, for most schools, will contain 26 kata. Some will have a few more, some a few less but a kata for every letter of the alphabet is about the number of these prearranged patterns we study.
The first 5 Heian kata serve as our training kata. Anything afterwards can only be as good as the technique learned in these five “basic” patterns. (There is an argument that the 6th kata, Tekki shodan is also one of these training kata because we do not give the time required to its study until after we gain our black belt).
Heian kata contain some of our most basic moves in a shorter set of sequences that most of our kata that follow. They set out rhythm, mechanics, hips, height control and allow us to build up essential speed, strength and balance.
After teaching karate for a few decades, I’ve seen tens of thousands of karate folk and not everyone takes to kata straight away. Some struggle with the memory aspect, others don’t see the point (other than to gain the belt). Some struggle with the relentless way we focus on these patterns, and some even over-think each move.
For those who are on the outside, Heian kata will increase in difficulty in terms of physical development so they align to next belt level. A simplistic overview of each kata:
Heian 1. First make some shapes and move in a rhythmical way. You may have to repeat this kata for the next belt by developing the shapes and the rhythm
Heian 2. Makes some more difficult shapes with an increase of the range of hip movements.
Heian 3. This kata seeks to increase the difficulty between transitions and develop the height control to influence balance and speed.
Heian 4. A dramatic increase in the difficulty in body mechanics, specifically the role of the supporting leg.
Heian 5. This final kata sees an increase in directional path difficulty.
Below. I perform Heian 3. I transition between front, back and horse(riding) stance and on three occasions I bring my feet together. Notice how the torso rises and falls in places and I try to remain the same height, despite the moves forcing a different reaction. I have to control the height in linear movement, turning and twisting and even standing on one leg.