The two characters that make up the name Unsu (雲手) are “Un” and “Su”. "Cloud" and "Hand" are their respective meanings. The word could be interpreted as "Cloud Hands", "Hands in the Clouds", etc. "Cloud Hands" is probably the best translation of the word “Unsu”. Probably it is a very ancient kata of uncertain origin adopted by Shotokan and Shito-ryu. In some ways it resembles to “Nijushiho” possibly belonging to Arakaki style.
The Shotokan's Unsu kata is distinctly different from the kata in Shito-Ryu called "Unshu". "Unshu" is obviously the source for the Shotokan kata. They are very close in technical performance, except that the Shito-Ryu version does not contain a jump nor does it have the fast rhythm of Shotokan's version of "Unsu" kata.
While these are the same kata, Shotokan’s has been revised almost specifically to appeal at tournaments in comparison to the Shito-Ryu version. This kata is and advanced kata for higher Dan and probably the most popular and effective tournament kata in the Shotokan Karate competition. A 360° turn leaping in the air is one of the techniques that is an effective crowd pleaser. The kata is also full of dynamic rhythm changes that make it beautiful to watch.
Masatoshi Nakayama suggests in 'the Best Karate' volume containing "Unsu", that the name derives from the constant transformations, expansions, contractions, shifting, etc. of the body as the Kata is performed, just as clouds constantly change and transform.
In 1922 Master Funakoshi published a book “Ryukyu Kenpo Karate” and “Unsu” appeared for the first time.
The Thunderstorm Theory
Some say the entire kata is supposed to be about a thunderstorm. The first movements where the hands spread apart are a squall line gathering on the horizon. The feet drawing circles on the floor are little dust devils being stirred up as the clouds approach. The pointed finger strikes are lightning striking the ground as the clouds come ever closer. Finally wind whips up and blows everything to the four directions - the four block-punch combinations in to North, East, South, and West.
The round kicks performed from the ground are supposed to be indicative of lightning and its true nature: It strikes from the ground upward into the sky. There is a calm in the storm as the hands spread apart. Then the true ferocity of the storm grabs hold of everything, to the North and the South as you fire techniques in these directions, constantly changing back and forth.
There is one more place of calm in the storm, and then finally, the giant leap is supposed to be a tornado. The kata ends with one final clap of thunder, and then everything is quiet. Perhaps “Unsu” was originally a folk dance on Okinawa performed to explain the rain, typhoons, and tidal waves.
“Unsu” means: “Cloud hands”
Gichin Funakoshi first mention "Unsu" in his book (Ryukyu Kenpo Karate) in 1922
“Unsu” is a kata practiced in Shotokan and Shito-Ryu
“Unsu” is one of the most popular and effective tournament kata in the Shotokan Karate competition
"Unsu" root : "Shuri-te" school of kata in Okinawa