The television commercial opens with a dazzling shot of Mt. Rushmore and the carved faces of four presidents with a lot of blue sky up above.

Then it shifts to a tall bluff suddenly swarming with jolly Americans who wave their arms and smile warm, welcoming smiles.

"America is calling," the narrator says.

The advertisement is part of an expensive Japan Air Lines "See America" campaign that is helping build a new record in Japanese tourism in the United States this year.

Japanese travelers are heading across the Pacific in large numbers, their purses and wallets crammed with yen that are worth about 25 per cent more than they were last summer. The rapid appreciation of their currency this year plays a part in the boom which, if current estimates hold true, will see about 830,000 Japanese spending more than $600 million at American hotels, restaurants and gift shops.

For the first five months of 1978, the number of America-bound tourists was 8 percent above a year ago.

So far, it appears that the rising yen is a marginal influence. Air fares, which are the major cost of touring abroad, are still pegged at a 1973 exchange rate, so the yen does not buy more until the traveler lands in the United States. What he spends for gifts, clothes and other items costs less than before. The $500 he took with him last year is worth about $625 this time.

A series of interviews with America-bound tourists at Tokyo's downtown air terminal turned up few whose travel decision was based on the higher valued of the yen. Some agreed that it was a welcome influence, though.

Hiroaki Otsubo, 23, and his wife cleaned out their savings for a Hawaiian vacation and if the yen were not so powerful they would have had no "use other measures to get the money to go." Besides, Otsubo said, his wife wants a leather bag and shoes and those items are much cheaper in America.

A young Osaka officeworker, bound with his wife to the West Coast, said they would have had to wait two or three years to go if his yen had not appreciated so fast in American values.

The marginal difference in currency value is enough to give the U.S. Travel Service a bargaining lever with the Japanese tour - packaging companies that handle half of the overseas tourists market.

"There is no saving on the airline passage because the exchange rates are fixed," observes Fritz M. Schmitz, regional director of the travel service in Tokyo. "What we tell them is once they get there, things ae a lot better this year."

The big change in Japanese tourism this year has less to do with currency exchange rates than with the new trend toward individual and small-group traveling. Groups trips are still enormously popular and the typical tourists still signs up with 50 or 60 friends and treks patiently around foreign streets behind a tour leader's raised flag.

But this year, more are trying it alone or in small groups. Japan Air Lines, the nation's flag carrier, has designed a "zero" tour which gives cut-rate charter-flight fares but then leaves the passenger to go where he wants in the United States.

Advertisements attempt to assure the "zero" traveller that he can make it on his own. One television commercial pictures a lone Japanese man driving a jeep through Grand Canyon. A state police helicopter zooms down and the pilot, through a bull-horn, asks if the young man is in trouble. The tourists replies that he is doing well be himself.

"Language is less of a problem for the young traveler today," said Hisashi Ito, general manager of JAL's international marketing. "They are more likely to speak English and not so likely to be embarrassed if something goes wrong."

The tour companies are not reducing their rates to take account of the yen's appreciation but many have held the line against price increases and some are offering a few extras, such as free wine in hotel rooms, to give Japanese at least a taste of their currency's new buying power.

There are indications, too, that the tourists spend more this year once they arrive in America cities.

"They are staying in better hotels and going to the best restaurants," said Ito, "and they are going for the optional tours, like the helicopter ride around Manhattan."

There is also a shift to the mainland vacation sites. About 40 percent of the Japanese tourists to America will visit the mainland this year, it is estimated. Usually, only about 25 percent of them get to the mainland, the rest settling either for nearby Guam or Hawaii.

Instead of stopping at previously popular West Coast cities, this year's traveler is more apt to go inland. Tour packagers are having success this summer peddling trips to New Orleans, Miami, San Antonio and Houston.

There is even a new fervor to visit "small-town America" far from the main tourist sites, and a couple of tour companies are selling something once unheard of among hear-traveling, bus-and-hotel-prone Japanese - a week on a dude ranch in Idaho.