What is the theme song to the Japanese movie with the English title, "The proof of man"?

Question

The movie was originally in Japanese, but I got a version of it dubbed into Chinese, and I loved the original Theme song. What was the name of the song or did it not have an official name? some lyrics from the song: Mama, do you remember, the old straw hat, you gave to me? I lost that hat, long ago, it blew into, the foggy canyon... (or something to that affect)

Answer 1

THE MAIN THEME OF PROOF OF THE MAN

Mama, Do you remember the old straw hat you gave to me
I lost the hat long ago, flew to the foggy canyon
Mama, I wonder what happened to that old straw hat
Falling down the mountain side, out of my reach like your heart

Suddenly the wind came up
Stealing my hat from me
Swirling whirling gusts of wind
Blowing it higher away

Mama, that old straw hat was the only one I really loved
But we lost it, no one could bring it back like the life you gave me

Singer: Joe Yamanaka
Lirics:
http://cgi.members.interq.or.jp/blues/yusaku/NINSHO.html

p.s.Yaso Hachijyo's lyric, "Boku no boshi" [My Cap], is the original lyric of The Main Theme of Proof of The Man. http://www.kodomo.go.jp/gallery/digi/KODOMO_WEB/authors/saijo_e.html