"Anyone who's been in battle recognizes there are great sacrifices made on both sides," said Queen Lilioukalani Trustee and former Hawaii judge Tom Kaulukukui.
"It's been in my family for nearly 70 years," he told KITV reporter Lara Yamada, holding the rifle his father gave him so many years ago.
But nearing the anniversary of the bombing of Pearl Harbor, Kaulukukui realized it was time to tell its story and return it home.
"He played a number of sports," he said of his father Tom Kalukukui Sr.
He was an outstanding athlete in Hawaii, an All-American who played many sports including football, baseball and volleyball.
By the end of World War II, he was on his way to Japan.
His team would win the Army Pacific Championship in Tokyo, but it was the prizes that stunned them the most.
"The team was taken to a room where he said there was a pile of captured Japanese weapons and they were told take whatever they want," said Kaulukukui.
"This translates to Okazaki Naval Air Group," read Japan American Society of Hawaii President Ed Hawkins.
When he heard of the story, he wanted to help.