Stories about international trade usually focus on factory-produced items such as automobiles and semiconductors or pieces of the service economy from banking to telecommunications.

But what about baseball?

A look at pitchers and hitters offers a different perspective on the changing nature of trade between the United States and Asia, especially Japan.

At New York’s Yankee Stadium, one of this season’s most popular player jerseys is that of fireball pitcher Masahiro Tanaka, one of three Japanese players on the Yankee roster, along with pitcher Hiroki Kuroda and outfielder Ichiro Suzuki. You can get a jersey with Tanaka’s last name spread across the back in English, but you can also wear a version in Kanji, the Chinese characters used in written Japanese.

Bill Dorman

While endorsements and advertising have played a role in Major League Baseball since its earliest days, there’s a new tone in this area as well. The names and corporate logos of nearly half a dozen Japanese companies are splashed around the outfield at Yankee Stadium this summer.

There’s nothing particularly new about this — Toyota, Sony and others have been doing this kind of marketing for years. But the Yokohama Tire Company appears to be a relatively recent addition, and tucked above the right field bleachers is a different kind of sign, advertising the services of an American company in Japanese. The Met Life display appears in the modified script version of characters known as katakana, designed in part to reach the Japanese television audience watching when Tanaka or Kuroda takes the mound.

But neither Tanaka nor Kuroda — nor even Met Life — would be pitching in the same way at Yankee Stadium today were it not for the work of another Japanese hurler who broke barriers nearly two decades ago.

The 1995 season belonged to Hideo Nomo, who made his first appearance as a Los Angeles Dodger, following a hard-fought legal battle and transition from professional baseball in Japan. He went on to win Rookie of the Year honors at age 26, and posted double-digit victory totals in seven of his 12 major league seasons in the U.S.

Nomo was not the first Japanese-born player in the major leagues. Masanori Murakami pitched his first game for the San Francisco Giants in 1964. But Nomo triggered a new wave. Since Nomo’s time, not only has the volume of transpacific baseball trade increased, the nature of that trade has shifted — on both sides.

Twenty years ago, conventional wisdom in the American baseball world was that Japanese pitchers might possibly compete at the major league level in the U.S., but that position players would not.

Outfielder Ichiro Suzuki shattered that myth when he started playing for the Seattle Mariners in 2001. Today, the pitcher’s mound is still the most common destination for Japanese players in professional baseball in the U.S., but they can be found all over the field.

Times have also changed for American ballplayers in Japan.

The first American player to take the field for a Japanese professional team after World War II was from Hawaii. Maui-born Wally Yonamine played most of his career for the Yomiuri Giants in the 1950s and into the early 1960s. Today he remains the only American in Japan’s Baseball Hall of Fame.

More than 20 years ago, most American players in Japan were in the twilight of their careers. Many teams favored power hitters.

One of the most entertaining extended reads about the cultural challenges for all players and teams involved around that time remains Robert Whiting’s classic, “You Gotta Have Wa.”

Today, it’s much more common for early and mid-career American players to spend time in Japan. A website covering Japanese baseball in English says major league scouts now consider Japanese professional baseball to be an AAAA league — a cut above the top minor league in the U.S., and just a step below major league baseball here.

Professional leagues have spread through the region, notably in South Korea and Taiwan. A pro league was started in the Philippines in 2007. Years earlier, Hawaii also played a role in the development of baseball in Asia. In the book “Taking in a Game: A History of Baseball in Asia,” author Joseph Reaves describes Hawaii as “a beachhead for American baseball in the Pacific.”

When St. John’s University in Shanghai started its first baseball team in 1895, two Chinese players from Hawaii were recruited as coaches. And more than 100 years ago, the “Overseas Chinese Team” was organized in Hawaii and traveled frequently to the mainland United States. In 1911, the team defeated the New York Giants in an exhibition game in San Francisco.

In more recent times, mainland China has not been a part of professional baseball. So far there is no Yao Ming equivalent to do for Major League Baseball what the towering Chinese center did for the NBA in terms of generating interest and excitement inside of China and Chinese communities elsewhere. But Asia’s presence in baseball’s major leagues has grown substantially.

There were 13 Asian-born players on major league rosters on opening day this season, according to the league’s commissioner. Nine were from Japan and two each from South Korea and Taiwan.

While those figures are nowhere near the 83 players from the Dominican Republic or the 59 from Venezuela, it does show that Asian influence on American baseball continues to grow.