Although it wasn't Baltimore's Memorial Stadium or even the sandlots of the Eastern Shore, Maryland Gov. Harry Hughes looked right at home firing off half a dozen pitches from the mound at Yokohama Stadium.

Hughes, who on Saturday ended a six-day visit to Japan, was seeking to generate goodwill and investment for the state. But at times, it has seemed the goal was more to prep him for a new political career here.

Besides exposure, he already has a key endorsement. "His character is sincere, vibrant and full of wit," declared Kazuji Nagasu, governor of Kanagawa prefecture after entertaining Hughes earlier this week. "He's a wonderful politician."

The visit was timed to coincide with a three-week tour by the Baltimore Orioles, who are here to play a series of exhibition games in Japanese ballparks. "They're very good goodwill ambassadors," Hughes noted.

But Hughes sees the trip in a more serious light. "We accomplished a lot," he said during the trip. Two Japanese companies announced plans for investment in Maryland and "there's another one that we're not at liberty to mention," he said.

It is Hughes' second visit to Japan as governor. He stopped here briefly in 1980 to sign a "sister state" agreement with Kanagawa, which contains the sprawling port city of Yokohama just southwest of Tokyo.

This time, he brought his wife Patricia, a security man, a half dozen state government officials and state Senate President Melvin Steinberg. Representing Maryland business were a dozen corporate and bank executives, including J. Owen Cole, chairman of the First National Bank of Maryland.

Hughes' press secretary, Lou Panos, estimated that the trip cost state taxpayers $50,000. Full expenses were paid for Hughes, his wife and the nonelected state officials; Steinberg and the business leaders paid their way, he said.

Currently, 33 Japanese companies are in business in Maryland, employing about2,000 people, according to Panos. The state maintains a trade representative office in Tokyo with a staff of three.

A decision by the Shimadzu Corp., a scientific instruments company, to begin manufacturing in Columbia, where it already has a sales and service outlet, is one of the two concrete successes the Hughes' delegation is citing. It will mean several millions dollars of investment, officials said.

The second case is Ando Electric Co., a spectrometer manufacturer that announced it had opened a sales and service office in Rockville with a view toward expanding later into production. Some of the final details for these deals were worked out during Hughes' visit, Hughes and Panos said.

The emotional high point of the trip came Wednesday, when Hughes and his entourage were driven to Yokohama. At government offices there, hundreds of people lined the streets to greet them. A band and a marching unit of majorettes performed.

Hughes and Gov. Nagasu discussed programs to exchange students and cultural exhibits and to construct a Japanese garden in Annapolis.

From there, they went to Yokohama Stadium, where the Orioles were to play the Hiroshima Toyo Carp, this year's national champion baseball team.

Hughes, who played briefly with a minor league team on the Eastern Shore in the 1940s, stepped onto the mound in a baseball cap and let fly repeatedly. The batter, 66-year-old Nagasu, swung unsuccessfully, let several go by, tipped a foul, then finally dropped the bat and headed for first.

Some Japanese watching the game noted with admiration afterward that when the catcher fired back one of the pitcher's balls at professional speed, Hughes caught it without hesitation.

Hughes' former career on the diamond aroused the curiosity of many people in the country, which has a longstanding love affair with baseball. "There seemed to be a quite a bit of interest in that, more interest than the career justified, frankly," Hughes said.

Hughes and his wife left Tokyo Saturday. They are taking a two-day rest in Honolulu on the way back, Panos said.