The lean years may be over for Akira Kurosawa.

Japan's most famous film director, the one with the largest international reputation, recently finished shooting his first Japanese film in a decade. It is the most expensive film ever made in Japan, and the critics' early judgment is that it is one of the best. The director is said to feel it can be a turning point in the country's depressed (and some say depressing) film business.

If those dreams are fulfilled, it will be partly because of a lot of help from Kurosawa's American friends Francis Coppola ("Apocalypse Now") and George Lukas ("Star Wars"). Until they induced Twentieth Century-Fox to come up with a $1.5 million guarantee in exchange for foreign rights to the movie, Kurosawa could not beg enough money from any Japanese producer. It is the first U.S. investment in a Japanese movie and Kurosawa hopes it will start a trend.

The film is "Kagemusha," a three-hour-long medieval epic filled with scenes of mounted Samurai clashing in one of the 16th-century civil wars that have so much romantic appeal for Japanese moviegoers. It is about a common criminal suddenly elevated to replace a lord who had, in the interests of clan security, ordered that his own death be kept a secret from his enemies. "Kagemusha" literally means "the shadow warrior," but that doesn't quite fit the movie's meaning, and there is still debate about a proper English title.

Critics who have seen most of the raw footage call it the most beautiful of all Kurosawa's films and believe it will rank in importance with his early successes, such as "Rashomon," "The Seven Samurai," and "Ikiru."

Most of the talk is of its spectacular camera work. "Professionals will be astonished at the technical skill," says Tokyo film critic New Kawarabata, who believes that Japanese films technically lag behind foreign ones. Donald Richie, a critic and author of a book on Kurosawa, calls it "the most beautiful film he has ever made."

Because the early judgments have centered on the technical artistry of "Kagemusha," some questions have been raised about its story and theme. The critics say it is not merely a full-color spectacular relying on scenery and dashing Samurai. But they also consider it less pointed in its message than such early Kurosawa films as "Ikiru" and "The Bad Sleep Well."

Richie said he believes it questions Japan's feudal militarism by using a common man "to expose the rigidity and bloody-mindedness of the Japanese view toward the wars. It opens a hole so that you can look inside that (feudal) structure and see what really went on. It's not muckraking, but it does contrast the official myth with human reality."

Kurosawa himself does not like to talk about whether the film carries a particular meaning. "There is no specific message," he said in an interview. "If I had a message, I would write it on a placard and walk around with it." Different people will see different meanings in "Kagemusha," he said, because it reflects the complexities in his own mind. "I don't like the idea of a film only doing one thing," he said.

Because it represents a comeback for the popular director, the making of the film itself is a kind of Japanese melodrama -- a story of the once renowned artist virtually abandoned by his native industry. Kurosawa, who turned 70 last week, literally went begging for the production money. As a tale of the fallen hero who endures and succeeds against heavy odds, the making of "Kagemusha" is as dramatic as any script he has written.

Kurosawa was one of two or three postwar Japanese directors whose work attracted international attention. "Rashomon," perhaps his best-known movie, won first prize at the Venice Film Festival in 1951, the first major international award for a Japanese movie. He followed it with several widely acclaimed films that ranged from Samurai dramas to social protests to simple humanistic stories of little people who struggle.

Along the way, he managed to alienate the men who run Japan's major studios. They complained that he overspent budgets and was late in bringing in almost every production. Kurosawa is also a volatile man to work for, given to denouncing actors and cameramen. His most common accusation is that coleagues don't think for themselves and leave every minor decision to him, according to a friend.

By 1970, the producers had had enough and refused to finance anything he offered. There was a disastrous experience in which Kurosawa quit or was dismissed from production, with an American company, of "Tora Tora Tora," a film about World War II.

The times were hard, and Kurosawa went into a deep depression. He attempted suicide by slashing himself more than 20 times with a razor, an act that a close friend describes as "more of a cry for help." He wrote a script for a Japanese version of the King Lear tragedy and another script based on an Edgar Allan Poe tale but found money for neither of them.

He recalls that long dry spell now as a period of hard work, writing scripts for movies that might never be made. "I was not just playing around," he said. In one of history's more novel movie-selling episodes, he composed more than 200 color sketches of scenes he hoped to direct in "Kagemusha" and trekked through production companies with them under his arm.

Like any rejected artist, he got angry, and his disgust with the small-mindedness of the studios is still with him. Last week, he took a brief break from last-minute sound-dubbing at the Toho Studio for an interview in which he explained his wrath.

"The motto of the film companies is 'Safety first,'" he said. "They don't have any spirit of adventure. They are satisfied to put up a moderately small amount of money and if it (a movie) comes out moderately good then they are satisfied. But making a film is nearly always a gamble and if you think you really want to make it and if you can get the audiences to understand then you can get large audiences. But the Japanese companies always look backward. They don't have a fighting spirit." j

During the bleak years, his mind was mostly on Japan's medieval period. His King Lear epic would have replaced the British throne and the king's three daughters with a Japanese war-lord who had three sons. Kurosawa said he became fascinated with the idea of what might have happened had the general's sons been as faithless as Lear's daughters.

"The nature of man was naked in those (medieval) times," he said. "Society was changing and we can have a clear image of man in those times." But the Lear film never got off the ground and Kurosawa turned all his attention to finding the financing for "Kagemusha."

Finally Coppola and Lukas got some backing from Twentieth Century-Fox and then Toho film agreed to put up $5 million, twice as much as any Japanese company has ever invested in a single movie. Only the U.S. company's offer persuaded Toho to go along. "Our company could not afford it if it were only for Japanese use," acknowledges Toho film President Tomoyuki Tanaka. "We needed another market."

(Coppola, who could not be reached last week, will see the first complete screening of "Kagemusha" in Tokyo this Wednesday. And a spokesman for Lucas said, "George has been a fan of Kurosawa's forever. And Fox felt very confident because they had the endorsement of both George and Francis.") The financing of "Kagemusha" tells a good deal about the state of Japan's movie industry, which has fallen far since it surprised the art film world abroad in the 1950s.

The industry consists today of three major companies, which produce fewer and fewer films, films that are by most critics' standards getting shoddier and shoddier. Audiences are disappearing. Last year, patrons bought about 165 million seats, compared to the more than one billion seats sold in 1958.The companies produced 40 percent fewer films than were turned out in 1960.

Desperate to regain audiences that have turned to television, hobbies and home entertainments, producers had until recently put their dwindling funds into sappy romances, science fiction, bloody and themeless Samurai dramas, and disaster epics. A popular and typical thriller is "Godzilla," a monster film based on King Kong. The most successful movie of 1979 was an animation called "The Galaxy Railway 999."

There have been signs in the past two years of a renaissance of more serious films, but producers also continue to chase after the teen-age market with love stories that went out of style decades ago, says Richie, the critic and film historian. They haven't been very successful. "They are making films for a phantom audience," adds Richie. "It doesn't exist."

Kurosawa is described by friends as hoping that his new venture will not only restore his name but also turn the domestic film industry around, making it more adventurous and less stingy. A big success for "Kagemusha" overseas would open the door for more big-budget movies that would earn their way in part by large overseas sales. The testing point will be the Cannes Film Festival next month. A festival representative already has seen most of the film and extended an invitation to show at Cannes. Acclaim there, critics believe, would be the key to future international tie-ups.

Kurosawa, who likes to dream on a scale as big as his epics, is already planning his next effort. It will be the King Lear script. Its theme is not modest. Kurosawa recently told an interviewer that it will "show how man should live in this world."