While much of the talk on American social media is about which Japanese players who competed this past weekend in their exhibitions against the Chicago Cubs and Los Angeles Dodgers will eventually play Major League Baseball, the real key to Japan’s baseball future was on the field at Tokyo Dome early Monday morning.

Monday’s official practice was preceded by a two-hour coaching clinic with former MLB stars Ken Griffey Jr, Harold Reynolds, Jason Kendall and Jeremy Guthrie demonstrating a variety of drills to coaches whose young players compete in Japan’s MLB Cup.

The quartet demonstrated fundamental elements of hitting, throwing, pitching and tagging runners to a group of about 20 coaches. Guthrie, who had great grandparents who emigrated from Japan over a century ago, previously pitched at both Koshien Stadium and Tokyo Dome in the 2014 MLB-Japan All-Star tour.