AMHERST, Mass. -- "Boys, be ambitious!" This exhortation, which has inspired generations of Japanese, was the parting admonition of American educator William S. Clark to his students in Hokkaido, more than a century ago.

Not long after Japan opened its doors to the West, the new Meiji government employed Clark, for eight and a half months, in 1876. Though he was in Japan only a short time, Clark achieved near legendary status and an enduring place in popular Japanese culture. He is considered the father of modern Japanese agriculture.

Yet most Americans have never heard of him. Who was William S. Clark?