I have this theory concerning the creation of the Kusanku Dai/Sho and Passai /Sho kata( Kanku/ Bassai) by Anko Itosu ( 1832-1916 ).If you watch the performance of the Yara-Kusanku it is apparent that the Itosu-Kusanku dai & sho are a simplifed version of the more complex Yara-Kusanku.The question to ask is why did Itosu create two new types of kata from a prexisting classical kata? Their is a school of thought that will propagate that Itosu is responsible for the genesis of Karate/Tode being remove from the arena of a combative skills to one of a Do/Michi discipline acceptable to the general public as a form of physical athlectics, thus the introducation of the Pinan kata into the Okinawan public school system.
Their is also another school of thought ( my theory) that Itosu may have found a need to create kata that are/can be used against Bojutsu.Their are around 20 classcial Bojutsu kata from Okinawan,that number alone indicates that their was quite a bit of fighting with the BO in Okinawan, it seems that their is more Bojutsu kata collective than from each separate Karate/Tode traditions of Shuri-Te, Tomari-Te, & Naha-Te.In the later part of the 19th Century ,Sanda Chinen created his three Bojutsu kata, Shushi no Kon, Shirotaru no Kon, Yonekawa no Kon, thus quite a bit of Bojutsu was being practiced on Okinawan at this time in the later part of the 19th Century. This is just speculation and conjecture on my part, but Itosu may have taken the Yara-Kusanku and the Passai and created two new Sho versions for the purpose of utilizeing two new kata to counteract the Bo.I base this theory on the fact that both the Kusanku/Kanku Sho and Passai/Bassai Sho contain waza from attacks with the Bo.While the older versions of Kusanku and Passai do not contain any defense from the Bo, as far that I can ascertain.So maybe Itsou is not responsible for the deluding of combative soundness in Karate, but instead of responding to a situation in a rational maner in the cultural nexus of the epouch inwhich he lived, or I maybe totally incorrect with my theory.
ken allgeier