I read Iain's book review on Anaku kata. It was one I wasn't familiar with, so I watched a clip of it.
It got me to thinking, in that kata there are sequences that are repeated in other katas. For example, the movements with the double knife hand blocks that are found in Kusanku. There is also the double punch/kick/punch sequence that we see in Seisan kata.
Do you think that this is evidence that the katas were once complete fighting systems passed on by someone and the kata was a repository of their information and was "encoded" differently based on what they thought was important?
Do you think that a system like Isshin-Ryu that eliminated some of the katas that were taught in other Shorin based systems was an attempt to weed out duplicate material?
When looking at the Pinan/Heian kata series, do you think it makes them more important as a complete fighting system or just prepatory for the katas the moves came from?