TOKYO — I'm so upset ... I was a friend ... I couldn't believe it."

This was all Prof. Gunji Hosono could say. A newspaperman had called on his home in Tokyo early Saturday morning and told him the news — John F. Kennedy, President of the United States, was dead.

Hosono had known him a long time, even though he had met him only twice, first when Kennedy came to Tokyo as a private citizen in 1951, trying to locate the skipper of a Japanese destroyer who had rammed his patrol boat. Hosono helped him.

The second time he met Kennedy, he had been specially invited to his 1961 inauguration.

There had been a friendship for years, with a letter as good as a handshake.

Hosono could manage only a few broken sentences Saturday. Then he said: "My daughter ... please talk to my daughter."

Haruko Hosono knew Kennedy well, too. In 1957, when he was a Massachusetts senator, he had arranged a scholarship for her at Georgian Court College, a Catholic school at Lakehurst, N.J.

"I stopped into his office to meet and thank him. The Senate was in session, and he was very busy. But he talked to me for 15 minutes and took me into the chamber. He went up to the gallery and waved down at me.

"He was plain and friendly, and he never changed."

She recalls that, when she visited him again after her graduation in 1959, "he was youthful and very boyish looking.

"In 1961, he was heavier and older, and looked like a man. He was much busier, of course. But he was still friendly and cheerful. You could joke with him, talk with him."

Miss Hosono and her father, who had translated one of Kennedy's books into Japanese, talked with him in his office for half an hour after the inauguration. She wore a fine Japanese kimono for the event.

"He was surprised to see me in a kimono. I guess I looked much more grown up.

"It was unthinkable ... I didn't think anyone could have a grudge. When I answered the call, I thought. it was by accident or illness. Then he (a family friend. who works for a. local newspaper) told me it was assassination.

"Please, I must be with my father. He is very upset."