Hong Kong (CNN)Growing up in Japan, musician Oki Kano never knew he was part of a "vanishing people."
His Japanese mother was divorced and never told Kano that his birth father was an indigenous Ainu man. Kano was 20 years old when he found out.
For decades, researchers and conservative Japanese politicians described the Ainu as "vanishing," says Jeffry Gayman, an Ainu peoples researcher at Hokkaido University.
Gayman says there might actually be tens of thousands more people of Ainu descent who have gone uncounted -- due to discrimination, many Ainu chose to hide their background and assimilate years ago, leaving younger people in the dark about their heritage.
A bill, which was passed on Friday, for the first time has officially recognized the Ainu of Hokkaido as an "indigenous" people of Japan. The bill also includes measures to make Japan a more inclusive society for the Ainu, strengthen their local economies and bring visibility to their culture.
Japanese land minister Keiichi Ishii told reporters Friday that it was important for the Ainu to maintain their ethnic dignity and pass on their culture to create a vibrant and diverse society.
Yet some warn a new museum showcasing their culture risks turning the Ainu into a cultural exhibit and note the bill is missing one important thing -- an apology.
'Tree without roots'
Kano grew up in Kanagawa prefecture near Tokyo, where he became fascinated with Jamaican reggae. Even without being aware of his ethnic identity, the political commentary underpinning the songs made an impression on him.
"Bob Marley sang that people who forget about their ancestors are the same as a tree without roots," says Kano, 62. "I checked the lyrics as a teenager, though they became more meaningful to me as I matured."
After discovering his ethnic origins, Kano was determined to learn more. He traveled to northern Hokkaido to meet his father and immediately felt an affinity with the Ainu community there -- the "Asahikawa," who are known for their anti-establishment stance.
But his sense of belonging was short-lived -- some Ainu rejected Kano for having grown up outside of the community, saying he would never fully understand the suffering they had endured under Japanese rule.
Yuji Shimizu, an Ainu elder, says he faced open discrimination while growing up in Hokkaido. He says other children called him a dog and bullied him for looking different.
Hoping to avoid prejudice, his parents never taught him traditional Ainu customs or even the language, says the 78-year-old former teacher.
"My mother told me to forget I was Ainu and become like the Japanese if I wanted to be successful," says Shimizu.