Yuriko Gamo Romer’s documentary “Diamond Diplomacy” examines the history of Japan-U.S. relations through baseball, connecting the sport’s development with questions of race, diplomacy, war and national identity.
The film traces baseball’s introduction to Japan in 1872 by an American educator and its subsequent integration into the school system. It follows the creation of professional teams, the arrival of American players in Japan and the eventual movement of Japanese athletes to Major League Baseball, culminating in the global stature of Shohei Ohtani.
Romer, who was born in Tokyo and raised in the United States, said she began researching the project 12 years ago. Although people from MLB told her Ohtani’s success made the timing ideal, she described that connection as coincidental. The production received a $600,000 grant from the National Endowment for the Humanities, but more than half of that funding was canceled in April 2025 amid cuts. Former U.S. diplomat Glen S. Fukushima subsequently contributed $300,000, enabling the documentary to be completed.
Author Robert Whiting, whose books brought aspects of Japanese baseball to an international audience, appears in the film. He describes Japanese baseball as older than judo and links its perfectionist approach and intense discipline to methods associated with martial arts.
The documentary also revisits Babe Ruth’s 1934 tour of Japan with an American League all-star team. Large crowds watched the visitors play against and alongside Japanese athletes as political tensions between the two countries increased. The film recounts the claim that Ruth’s tour may have helped delay conflict, as well as the story that he discarded his Japanese souvenirs after learning of the attack on Pearl Harbor.
“Diamond Diplomacy” covers baseball played by Japanese Americans held in wartime internment camps, and considers how the sport helped confront prejudice after the war. It also examines tours by Negro League teams, whose players were often treated more favorably in Japan than they were in the United States. Japanese hosts praised their respect, humility and sportsmanship, contrasting those qualities with the arrogance they associated with some visiting white teams.
Masanori “Mashi” Murakami, the first Japanese player in MLB, is another central figure. He made his debut for the San Francisco Giants against the New York Mets at Shea Stadium in September 1964 and played alongside players including Willie Mays. Murakami recalls using the song “Sukiyaki” to settle his nerves before games.
After a Tokyo screening, Murakami said his initial motivation for traveling to the United States was not a major-league career but his enthusiasm for the television western “Rawhide.” He also recalled an incident in San Francisco when he confronted an umpire over a disputed call. Later, a Japanese restaurant chef thanked him, explaining that his response represented a source of pride for Japanese people who had felt obliged to be submissive toward Americans since the war.
The film further explores the experiences of American players in Japan, including the difficulties some faced adapting to demanding training methods and unfamiliar customs. Strand Releasing acquired North American rights, while Wondergenic took the film for Japan.
Sources: The Hollywood Reporter.