Good question,
@Grey shifu! For it all to make any sense, there a couple things to keep in mind.
Karate and its kata have undergone several, let's call them "marketing changes," over the years.
Okinawa's position between Taiwan and Japan made it a trading hub, and prior to the Japanese invasion the Ryukyu Kingdom had closer ties to China. Chinese culture was much more trendy at that time, and you can still see a lot of that influence in traditional architecture and fashion. Some individuals who came to stay in Okinawa brought their martial arts practices and shared them, and some Okinawans traveled to China to deepen their own studies, bringing back what they had learned.
Many kata have roots in Chinese martial arts, or are nods to specific individuals.
I'll start with the first one and I'll research and answer the others later, because I think this explanation sets the stage for the others in your list, and it's already quite long.
1. Kanku dai
I once created an AMA thread on the Karate Nerd Facebook group and was asked about the various pronunciations of this kata, so I'll plagiarize myself a little here. Addendums are in purple and italicized:
As we know, the history and evolution of Karate has happened in stages between four different entities: the origins in China, which then spread to Okinawa, and on to Japan, and eventually, the rest of the world. This means that the names of things have passed through several languages before they've arrived at our doorstep. The shared use of kanji with different pronunciations, and then the history of the different lineages, has led to a variety of names used today that are as varied as the kata themselves.
Now we can sprinkle a little bit of linguistics in. Like I said, I'm not super familiar with uchinaguchi... or any Fujian dialect, let alone the one spoken in the 1600's, So there's a bit of a disconnect there. As I understand, Uchinaguchi is much simpler phonetically (with fewer vowel sounds) than Chinese and Japanese, so it seems like many words and phrases are the result of bring Chinese to Ryukyu, and then transliterating it into Japanese. This is still apparent in certain styles, just look at the Goju kata names like Saifa, Seiyunchin, Suparinpei, and kururunfa; they contain sounds that don't exist in Japanese, and they're often written in katakana these days. When you learn what they mean, you can see how it's kiiiind of like onyomi, but not quite (probably because the origin is an old Fujian/Hokkien dialect, and it passed through the local language). If they were written in kanji, the meaning would be obvious, but no one could sight read them and guess the pronunciation.
You didn't ask about this one but I think it's worth leaving in:
I also found an article that suggests many different possible names for naihanchi that point to possible origins and meaning, ranging from "horse stance/step battle" to "inside leg step" to "battle between the rice paddies". Certainty in what is true has been lost over time, and all of these variations have been used in one school or another:
- naihanchi
- naihanchin
- naihanchen
- naifanchi
- naifanchin
- naifanchen
- naifuanchi
- naifunchin
- mafuchin
- mahochin
In Shotokan karate, this name has been changed completely to 鉄騎 (Tekki, iron horseman), more on that below. The meaning is similar but the word is very different, which fits into the pattern of modifying karate terms to appeal to the Japanese.
The consensus seems to be that the kusanku/kanku kata is named for a Chinese diplomat from Fukien (modern Fujian) who came to Okinawa around 1750 and despite being slight of stature, displayed such prowess that he was sought out as a martial arts instructor. As I understand it, Kanga "Todi" Sakugawa was encouraged by his teacher Peichin Takahara to study under him, and after some years of training, consolidated what he learned from him into a kata that he named for his teacher posthumously. The Chinese diplomat was known as 公相君 (possibly "kōsōkun), which was likely a title or given nickname meant to praise him. His actual name may be lost to the ages (how crazy is THAT?!).
Peichin and Todi were also titles of honor; Todi being the old name for Karate itself: 唐手. 唐 meaning the Tang dynasty, aka China at the time, and 手 meaning hand. Although it's often written "Tōdi," it was also written as "Tuidi," which I think is perhaps closer to the actual pronunciation in Okinawa. I'll need to consult with a native speaker to be certain. The name pointed directly at the origin for a long time: Chinese hand. In Japanese onyomi (the "sound" readings of kanji that came from Chinese), 唐手 would've been tōte, and the kunyomi (Japanese native reading) was "karate." This "kara" kanji is still used today for 唐揚げ/karaage, fried chicken. Don't ask me why.
Okinawa had much stronger cultural ties to its neighbors to the west than Japan up north; up until the 1800's they were a tributary of China and a vassal of Japan (after the
Satsuma invasion), serving as a conduit through which trade flowed. In the late 1800's, due in part to a failure of diplomacy by US President Grant, Japan just annexed the whole archipelago in 1879, then set out to colonize Ryukyu, shaming them out of their local culture and language, and shifting the trends to cater more to Japanese. It's not a very happy story for the Okinawans, I'm afraid.
In order to make karate more palatable to the Japanese, the Chinese connection would need to be downplayed.
Enter Gichin "Shoto" Funakoshi, a student of Yasutsune "Anko" Itosu, who himself was a student of Soken "Bushi" Matsumura, who reportedly trained under Todi Sakugawa.
This part is my editorial assumption: both Itosu and Funakoshi wanted their art to thrive; they knew which way the wind was blowing, and they would need to appeal to the colonizers to spread their art. So they assembled a group of masters and decided to change the name from 唐手/karate/Chinese Hand to 空手/karate/Empty Hand, distancing the art from its roots, and started promoting and marketing it for building healthy, strong bodies.
The timeline is a little fuzzy for me, but many changes were made as a result of this meeting, and karate was adopted as part of the school curriculum first for Okinawa, and then throughout Japan as it proved to be effective at physically conditioning the youth. For a country with imperial aspirations, this was a valuable resource to help hone the future generation of soldiers. Uniforms and belts were borrowed from Judo, and I imagine a lot of the formalized structures, practices, and etiquette of karate were also introduced both to create an easily replicated curriculum and to create a sense of order, hierarchy, and systematic approach to fighting arts. Having some experience training "the old way," I realized that a lot of the elements we associate with karate are more Japanese than Okinawan, and are far less "traditional" than we imagine.
And this brings us back to the 公相君 kata names. Most styles retained some version of the name based on the original 公相君 moniker, with the noted exception of kyokushin and shotokan:
- Isshin-ryu: Kūsankū クーサンクー
- Kyokushin: Kankū 観空 (Dai 大)
- Shito-ryu: Kōsōkun 公相君 (sho, dai 大, and shiho kosokun 四方公相君)
- Shorin-ryu: Kusanku クーサンクー or Kushanku, depending on sub-style. Sometimes still written 公相君
- Shotokan: Kankū 観空 (shō 小, dai 大)
- Shotokai: Kwankū 観空
- Wado-ryu: Kūshankū クーシャンク
- Tang Soo Do and Tae Kwon Do: Kong Sang Koon 공상군, the Korean pronunciation of the hanja 公相君
My thought is, just like the name of Karate itself had been changed to cater to the Japanese, so too did the kata names and terminology
for Shotokan, which was more or less the style that was spread throughout Japan. It's also worth noting that in order to scale up to the national education system, a whole lot of people were hastily made into karate sensei, which has had a haphazard effect on how it's practiced around the country.
Pinan (the Okinawan pronunciation of 平安, which already may have been changed from something else) became
Heian, the Japanese onyomi. Naihanchi became Kiba-dachi/騎馬立ち/horse stance and later Tekki/鉄騎/iron horseman. And of course, the point of this whole meandering story, is that Kūsankū became Kankū, or "looking to the sky," supposedly named after the initial moves of the kata.
So where do the w's come from? Well, when we look up the first character:
https://dictionary.goo.ne.jp/word/kanji/%E8%A6%B3/
One definition of 観 is 詳しく見る, to look intently/in fine detail. This is pronounced "kuwashiku miru." This may just be a coincidence, but then we see that the onyomi of the old form (觀) is クヮン, kwan. This sound doesn't exist in modern Japanese words, and it is produced using a compound kana like I mentioned above. And so when the name changed to 觀空 it may have been originally pronounced "kwankū," or possibly even "kuwankū," which isn't THAT far off "kūsankū." But like I mentioned about the chouonpu getting dropped in transliteration, it's most commonly spelled simply, Kanku. sho 小 and dai 大 denote the "small" and "big," AKA "short" and "long" forms of the kata.
At least, that's what I've been led to believe.