Both kata are fundamental to the schools that use them as the base kata of their lineage, but to say that they contain everything a karateka should know about the art and the combat is misleading IMO put simply although they contain the fundamentals of a style they are not inclusive. There are no kicks in sanchin, for example. Coming from a Goju background, sanchin is my beast, and boy what a beast. Early on I thought it was merely a muscle developing exercise and useful for upping the body's pain threshold but no. The great masters of the past would not have given such huge importance to these kata if they were not hugely important. To view them as anything less than hugely important is missing the point, IMO. It was after achieving dan grade that I really started to get to grips with sanchin, a bit late really, but possibly a process I needed to go through. Sanchin shows us how to generate tremendous power from a variety of sources, and together these then can manifest in all techniques. For example projecting our bodyweight into a technique whilst maintianing a stable base to ensure correct use of ground reaction forces through stable body alignment is necessary for both a simple punch as well as a spinning back kick to the same degree. Do either without bodyweight or with poor alignment and our kick or punch is weak. Sanchin teaches us this, and more. But beautifully it does so from such a "basic" form. There is of course so much more. But in Goju the application of Sanchin in all other kata is essential, even with GDI where it is obvious. But with other high grade kata also containing sanchin movements within the kata, e.g sanseru, the importance of sanchin is oncce more emphasised. The essence of other kata clearly require sanchin to manifest properly, it is in the kata themselves!! The originators of these kata didn't include such moves for fun ...............! In his outline of karate-do Miyagi also includes tensho as one of the fundamental kata with the two of this post
