Kyoji Yamamoto is probably the most famous rock guitarist in Japan. As leader of the groups Bowwow and Vow Wow, he has performed around the world, lived in the U.K. and the United States and played with some of the best musicians on the planet. Of course, hard rock in Japan struggles to compete with the saccharin dross that is J-pop, but there are very few J-pop artists who are sought out by their Western peers.

Six years ago, when Metallica visited Japan, drummer Lars Ulrich had one thing on his mind: to find Kyoji Yamamoto. Ulrich instructed his staff to track down Yamamoto and set up a meeting. They had crossed paths before.

"The first time I came across Metallica was 1987 or '88 at The Marquee Club in London," Yamamoto explained in a Tokyo cafe. "We were playing there and all the members of Metallica came backstage to see us. They were singing 'Silver Lightning,' which is a song of mine from 1977. I asked them why they were singing it and Lars told me they used to copy all my songs."