Willy’s father John Cahill was an instructor studying and working with Danzan Ryu Jujitsu founder Henry Seishiro Okazaki.

John taught judo and jujitsu to American servicemen stationed on the Islands throughout World War II.

Shortly after, he moved the school to South San Francisco where he taught for nearly fifteen years.

As a coach, his San Bruno Judo Academy won nine straight California championships in the 1970's.

One of Cahill's students, Corinne Shigemoto, has been named a U.S. Olympic Judo coach.