After the bitter war between them, Japan and America swapped TV sets and colas and became great good buddies. Both governments say.

But if the two countries are (as everyone suspects) going to be thrown closer and closer together in their roles as democracies in a nondemocratic world, maybe the trust and respect between the two nations needs more than some hearty corporations to rest on.

And almost surely, music and pictures and books-the whole rich culture-will vear more weight and stand greater strains than a few Sony's and colas.

At the National Academy of Sciences last night, 700 people turned up for the opening ceremonies of "Japan Today," a nationwide celebration, you might say, of Japanese culture and thought today.

The two-month schedule of panel talks, art shows, drama, movies, reviews of karate and tea ceremony and flower arranging and much else, officially began in Washington last night. Things will continue to pop through mid-June in the capital, New York, Chicago, Denver, Los Angeles, Boston and Miami, underwritten by money from the two Endowments (arts and humanities), the Matsushita Electric Corporation of Japan and the Japan Foundation.

In the best Western tradition, seven little talks were made by dignitaries representing the city government, the Academy, the Endowments and so on.

Thunderous applause greeted Masaharu Matsushita, chairman of the Japanese company, who said this was his first talk in English and would therefore be quite brief.

The Japanese envoy extraordinary to the Permanent Mission of Japan to the United Nations, Mrs. Sadako Ogata, was chief speaker, inspiring a lot of women to say afterward that the women quite outshone the men.

She touched on a delicate matter: There are odd misconceptions in each country about the other.Progress is not going to be like lightning. She touched on the "rigid" school system of Japan as one example of an institution that could stand a bit of progress, and delicately hinted that America should not throw out everything when annoyed with Japanese trade policies.

She was not about to catalog American shortcomings but her central point was that both countries need a more humanitarian and international outlook and greater experience in seeing things from viewpoints other than their own.

The Japanese culture festival, therefore, seemed to her made to order to advance the great project of each country's learning a bit more about the other.

One speaker valiantly contradicted Kipling-East is East and West is West and the twain meet. But Philip Handler, president of the Academy, mentioned his first visit to Japan was to establishr scientific supervision of the results of the atom bomb damage. It seemed likely there might be some Japanese who do not think America is totally splendid.

And at the party given following the ceremonies by Ambassador and Mrs. Fumihiko Togo at the new Japanese Embassy, it was necessary to post a sign saying no drinking or smoking in the Tea House.

A Japanese would not need such reminders. Things almost sacred and close to the center of life in one nation are easily thought quaint or even cute in the other.

Ogata's argument was that an extension of learning and sympathy between the two cultures would be the great base for long-range understanding, far more than even business interchange. She would like to see a similar program in Japan about America Today, she said.

What must have been several tons of outstanding Japanese shrimp and meat dishes gradually disappeared.

The Western gullet is sometimes the first avenue to comprehension of Japanese splendor and attention to detail.

The softly lighted waterfall of the courtyard carp pool was easy to appreciate, too. (The embassy, along with Western fanciers, lost their beautiful Japanese carp in gold and scarlet and black and blue and salmon and lemon thanks to vicious Washington winters.)

"The only thing," said Mrs. Togo, "that has not been a success."

The food was, the tremendous white flowering cherry was, the polish of the Japanese bowing to people was, and it is expected that some where between masterpieces of Japanese lacquer and a film on karate, a great many Americans will come closer to Japanese heritage. CAPTION: Illustration, Logo from "Japan Today,"; Picture, Mrs. Sadako Ogata at the opening ceremonies; by Harry Naltchayan.