IT WAS "Superman, The Movie," "Star Trek, The Motion Picture" and now, "Shogun, The Week." Considering the five-night, 12-hour of what's being bally-hooed as a "maxi-series," maybe NBC should have promoted it as "Shogun, The Way of Life."

Beneath the bombast, "Shogun" is a most honorable television production. The serlialized TV version of James Clavell's novel begins tomorrow night at 8 on Channel 4 with a three-hour first chapter, continues Tuesday through Thursday nights with two-hour installments, and ends with a three-hour finale on Friday. Even without the actors' strike that has decimated the competition on other networks, "Shogun" would be The Thing To See on television this week.

"Shogun" is rich, rousing, exceedingly handsome and refreshingly eclectic; the film was shot entirely on location in Japan, and the change of scenery from the usual visual monotony of television is wonderful. But pardon me for not jumping through a hoop, because this film about a British sea captain marooned in 17th-century feudal Japan suffers from the mini-series curse of exessive, unwarranted length, from a crucial casting blunder and from inscrutabilities of exposition that occasionally render it senseless.

Probably no film could be radically riveting for 12 hours, nor should be. Actually "Shogun" comes to just over 10 hours without commercials. Within those 10 hours are about four hours of exceptional entertainment -- swashbuckling worthy of Errol Flynn, an engaging romance, welcome teleportation to another time and place, and a background of political and economic intrigue. A 10-to-4 ratio is not bad for a longform television production, but it means that much of "Shogun" can be watched casually, with a book on one's lap, like most TV shows.

When the story begins in 1600, British navigator John Blackthorne has successfully piloted his ship to Japan, which he believes to be an unspoiled source of trade and wealth. But the ship runs aground; Blackthorne and his surly Dutch crew are taken captive. At first repelled by the values and customs of the Japanese -- including what he considers the vulgar habit of bathing an entire body in a steaming tub of water -- Blackthorne grows to respect them and, because of his military prowess and feisty pride, they him.

Lord Taranga, a local warlord believed destined for the title of shogun, or supreme military leader, takes a shine to Blackthorne and supervises his instructions in the ways of the samurai. But other Westerners have already arrived in this ripe-for-plucking land: crafty Jesuits who see Blackthorne as a threat to their mercantile interests and try to have him assassinated.

Blackthorne's other narrow scapes include temporary blindness after an explosion, the threat that if he fails to learn Japanese in six months an entire village will be massacred, and the murder of an old gardener who made the mistake of messing with Blackthorne's pheasant. Blackthorne also has a whispery affair with a beautiful lady samurai already married to the village chieftain.

There's a lot happening, all right, but the combative forces maneuvering for power, with Blackthorne in the middle, never quite reach the dramatic crescendo the script has primed us for. In the last hours, it's almost as if the film and money ($22 million) ran out, so somebody said, "Let's wrap it up, boys" -- abruptly and arbitrarily.

Two culprits spring to mind as likely botchers. One is author Clavell, who as executive producer of the program, probably had too much control over the project and its fidility to his enormous book -- now reissued to the tune of 2.5 million paperback copies peddled, it would appear, around every corner in the Safeway. Eric Bercovici wrote the script, but Clavell's name is omnipresent -- "James Clavell's Shogun," it says at each commercial break and in all promotional material.

Clavell may have a great agent, but he could use a bit more self-restraint. Bercovici's script builds up to spectacular incidents that either never occur or occur off-camera. A promised sea battle between the hero's vessel and "The Black Ship,' a prehistoric superliner, goes phfft when one of the boats burns to a crisp after a tidel wave. Neither burning nor tidal wave are shown.

In addition, the ascent of a key character to the position of shogun, and the civil war that must be fought to put him there, is made to seem the logical culmination of the story. But near the end of Hour Twelve this metamorphosis is glossed over with a few lines of narration from Orson Welles and a brief montage of vague battle scenes. Viewers have been cheated out of the spectacle that would end this ordeal with an emphatic wow instead of letting it dribble off as the book did.

It was pure stupidity not to spruce up "Shogun" for the visual and dramatic demands of television; even the most minimally gifted professional hack could have seen that the story required more action and less Fun Zen -- the Bercovici and Clavell recipe for a happier life through Introduction to Eastern Philosophy.

"A man's fate is a man's fate," we are told early in chapter one, "and life is but an illusion." Such obseversations riddle the script redundantly. "Life and death are the same," the heroine notes in Part Two, Hour Four. "Life and death are the same," she repeats in Part Three, Hour Six, adding, "Tomorrow does not exist. There is only now," and soon repeating, "Tomorrow does not exist."

By this time the hero's European prejudices are wilting because he says, a little later in the same hour, "Tomorrow does not exist."

This would certainly be a blow to Little Orphan Annie.

The crucial casting of Richard Chamberlain in the lead role of John Blackthorne, first Protestant to navigate his way to "the Japans," was camlamitous. Chamberlain does not have the stature, authority or bravado either for the role or to sustain interest over five nights. He makes a paltry Gulliver, standing about passively while things happen to him. There must be a million reaction shots of Chamberlain and they vary little, whether he is beholding a fair maiden disrobing in front of him or watching a crew member being boiled in a pot.

However, the Japanese actors are with few exceptions magnificent. Toshiro Mifune is imposing and grand as Toranage, a powerful general; he is the absolute soul dignity and a magnetic figure on the screen, as he has been in many Japanese films. As Mariko, with whom Chamberlain shares an inevitable Forbidden Love, Yoko Shimada may make the kind of beguiling impression on American audiences that Miyoshi Umeki made with "Sayonara" in the '50s.

The vision of Japanese womanhood may be wishfully romanticized (a Hollywood writer's dream, as it were) but it remains inescapably attractive. Among many others who distinguish themselves are Frankie Sakai as Lord Yabu, a samurai warrior who cannot be trusted. In part one, an unbilled Japanese actor in a small role makes a devastating impression when he commits seppuku, or hara-kiri, on camera, but with only his face showing -- a tour de force if there ever was one.

The first three hours are so heavy on tumult that they make later chapters seem relatively uneventful. "Shogun" begins with a storm at sea and a shipwreck. Within the first half-hour, a Japanese head has been lopped off on shore because a peasant refused to bow to his samurai superior. The crew of the ship are tossed into a pit and later one of two of them face the dread pot. Blackthorne suffers the indignity, probably a first for television, of being urinated upon by one of the samurai he has insulted.

Director Jerry London moves some sequences -- especially combat -- along very effectively but lets many a discussion keel over with a splat. He is strictly of the utilitarian, bare-bones school of TV movie direction, but here and there he manages to touch that connects, as with a shot of two giggling little girls who are among the first Japanese Blackthorne sees. In Part Four, Hour Eight, Shimada, as part of a ritual, sheds a tear on a leaf held by her husband. London captures the delicacy and eloquence of this very neatly.

Bercovici's script has its own little landmines, however, and the abundance of untranslated Japanese dialogue does pose some problems. Mariko can speak English, so things are fairly intelligible as long as she stays in the scene. When Chamberlain is left alone with characters who speak only Japanese, the film runs adrift. Bercovici also likes to stage inexplicable events like attacks in the night and not explain them to the audience until much later.

It's not much comfort but somewhat empathetic when Chamberlain shouts, twice, in the (literally) eleventh hour, "What the hell is going on?" or when Shimada notes in Part Two, Hour Four, 'Please excuse me, but that does not make sense."

Blackthorne's crew disappears after chapter one and they are not seen again until chapter four. Blackthorne never seems to inquire about them or express any interest, and his first line upon seeing them is unintentionally funny: "Listen, has anyone seen the ship?" Bercovici zings a few other risibles, particularly when he tries to simulate 17th-century cussing, as in Blackthorne's grumble, "Those sons of plague-infested lice!" or another character's exclamation, "Madonna, what a pig!"

Shimada not only provides the romantic interest but also summarizes the plot now and then and serves as a tour guide to the customs of the country (customs that not everyone agrees are authentic, incidentally). She refers to Blackthorne as "anjin-san," anjin meaning pilot, and must give credence to such breathy sentiments as "You have a honey tongue, anjin-san."

When Blackthorne and Mariko fall in forbidden love, they resort to thee-thou talk: "Thou art beautiful," "I love thee," (yet, soon after, "You seem very happy today," "You know why"), "Thou art magic for me," and "I desire thee." Pretty thick.

Decidedly a highlight, however, is a discussion of the ups and downs of "pillowing," the word used for sexual relations, in Part Two. "You haven't pillowed since you've been here?" Blackthorne is asked. "You must feel constricted." Improbably, and ridiculously, he declines the offer of a mistress ("Uh, perhaps later") and takes noisy umbrage when offered first a woman, then a boy. Blackthorne's umbrage gets very wearing.

Themes of culture clash and the relativity of what is considered alien are not subtly established, but they give "Shogun an illusory air of importance that does lift it slightly above the usual adventure tale. More adventure and less importance would have been advisable, but "Shogun" is hardly a cheat, and the hours spent with it are not a waste, as most television is.

The luster of the production is a boon and a comfort. Maurice Jarre's musical score gives invaluable manipulative support. As Blackthornes's ship The Erasmus, The Golden Hinde II, which NBC says is a replica of Sir Francis Drake's galleon, cuts a striking swath across the screen. Andrew Lazlo photographed the Japanese locations beautifully.

"Karma is Karma," Blackthrone observes as his occidentalism fades away, and America's karma is probably to spend the week ahead with "Shougun." The serial may in fact constitute the first great wave in the Easternization of the '80s and it could do much to popularize or re-popularize Oriental culture and fashion here.

PBS is well into "Television from Japan," five programs from Japan's NHK public television. The most influential network documentary of the summer was Reuven Frank's "If JapanCan, Why Can't We?" on NBC; the network was deluged with requests from U.S. corporations for transcripts and videotape copies of this report on the reindustrialization of Japan and how it may hold an answer for the current crisis in American productivity.

Shogunning may not be the ideal way to experience another society, but the air it brings to the usually claustrophobic world of prime time is decidedly fresh and sometimes exhilarating.