It is said that Kushanku, or Kong Su Kun, learned Chu'an fa kung fu from a Shaolin monk. He was sent to Okinawa in 1756 as an ambassador to the Qing Dynasty and resided in Kanemura, near Naha City.
We probably would like to think of our karate ancestors as being well-mannered men of wisdom, but even wise men begin as passionate and foolish youths. Kanga Sakugawa was very daring and mischievous at twenty-three and one night contrived to push the visiting Chinese dignitary into a stream for the fun of it.
But, the Chinese diplomat Kong Su Kun used his own martial arts knowledge to turn the tables on the young prankster. Sakugawa was shamed and humiliated, and was forced to humble himself and apologise.
In his mercy and wisdom, Kong Su Kun invited Sakugawa to become his student and study “White Crane Chu’an Fa” with him. Along with the enthusiastic support of Takahara, Sakugawa accepted the invitation and trained with him for six years, until Kushaku's return to China in 1762. He died in China in 1790.
At the time, the White Crane system was a new and exciting development, and Takahara probably expected to learn about it through his student. While he studied under Kong Su Kun, Sakugawa was introduced to the principle of “hikite”, the pulling back of the hand (like we use in karate today).
Sakugawa developed the kata in honour of his teacher, which became Kushanku, or Kanku-Dai as we know it. Sakugawa was not as experienced in chinese martial arts as Chatan Yara (another of Kushanku's stidents) and did not know the principles of the Chinese martial arts. Due to this he cound not reach the depth of the martial art of Kushanku even though he learned from Kushanku for six years until his departure in 1762. So he modified the Kata Kushanku he had learned, as Chatan Yara did, and replaced many techniques he did not understand by techniques using power. By this he changed the Kata heavily and the original content was not taught to Sakugawa's decendents.