Kankū-dai (観空大), is an open hand karate kata that is studied by many practitioners of Okinawan, Japanese and Korean karate. In many karate styles, there are two versions of the kata: Kankū-sho and Kankū-dai. The name of the Kata differs across Karate styles however the original name, Kūsankū (クーサンクー) or Kōsōkun (公相君) is used in Okinawan systems of karate, and refers to a person by the name of Kūsankū, a Chinese diplomat from Fukien who is believed to have traveled to Okinawa to teach his system of fighting. In Japanese systems of karate, the kata has been known as Kankū (translated as gazing heavenward, viewing the sky, or contemplating the sky) ever since it was renamed in the 1930s by Funakoshi Gichin
Kankū-dai is a cornerstone of many styles of karate. It is characterized by the use of flowing techniques that resemble those found in White Crane Kung Fu; it also has a wide variety of open-handed techniques. In Matsubayashi-ryu karate, the kata is known for its flying kick and its “cheating” stance, which robs the opponent of opportunities to attack by extending one leg along the ground and squatting as low as possible on the other (ura-gamae). One possible bunkai for this technique allows the practitioner to escape a bear-hug from behind by twisting and dropping out of their grasp. The hand techniques that accompany the stance block the head, while allowing for a strike to the groin, knee, or foot. Because of the complexity of its techniques, Kankū-dai is the highest ranking and most complex kata in Matsubayashi-ryū, and is said to take more than ten years to master.
In Shotokan karate, Kankū-dai consists of 65 movements executed in about 90 seconds, and symbolizes attack and defense against eight adversaries. It is a major form of the kata; its equivalent minor form is called Kankū-shō. Kankū-dai was one of Gichin Funakoshi’s favorite kata and is a representative kata of the Shōtōkan system. The embusen (path of movement) of Kankū-shō is similar to that of Kankū-dai, but it begins differently. It is a compulsory Shōtōkan kata and of high technical merit. As a result of Anko Itosu’s efforts, the Heian kata contain sequences taken from Kankū-dai.
This post on Iain Abernethy’s website demonstrates the first few moves in Kanku Dai and the meaning of angles in the Kata: Kanku-Dai / Kushanku Bunkai Drill – Opening Moves (video)