And now, for something totally different

Isn't it time for something truly new under the fashion sun? Not that the clothes we've been wearing, based on directions from Paris, New York, and Milan, aren't all well and good. But aside from seasonal variations in shape and color, styles in the Western world have not undergone any deep-down changes to speak of in recent years. They keep following accepted precepts in line and cut. As a consequence, even your very latest dress or jacket looks rather like what you bought last time (which may, in fact, be reassuring).

Does this mean we are in a sartorial rut?

Some Japanese designers think we are. Radical innovators of a new school out of Tokyo, they are out to shatter the traditions of establishment dress. Their iconoclastic ideas - like those of Rei Kawakubo (who has been described as having ''the purest vision and the most powerful approach'' of the new group) have in some quarters been met with derision, ''Bag Lady Intellectual'' being among the epithets. Yet in others, they've been heralded as ''the fashion of the future.''

Kicking over the fashion traces, designers like Kawakubo suggest that we forget about such conventions as indented waists, straight hemlines, and, for that matter, the regulation pair of sleeves.

''I try to empty my mind from all previous influences, ethnic and cultural, and work from a form state,'' says the diminutive designer whose Comme des Garcons (like boys) label is regarded by progressive retailers and their avant garde customers as the hottest around.

The most cerebral of the Far Easterners, Kawakubo approaches her work as does a master of hand-thrown pottery, whose choice of clay and methods are integral to the artisanry of the finished product.

Kawakubo, a university graduate with a fine arts degree, took her early training in textiles. The fabrics she makes are the basis of her creations. Starting with the selections of threads and yarns, her procedure involves pre-washing and drying in natural sunlight.

This preliminary process, which usually takes six months or longer, results in fabrics akin to those worn for centuries by Japanese workers and farmers.

As viewers of her startling ready-to-wear presentations in Paris have noted, black - Kawakubo's favorite - is the dominant (and often unrelieved) color. Her mannequins, unlike others in the Japanese contingent (whose faces were decorated with savage streaks), wear no makeup whatever.

Waistlines may be nonexistent or indicated by wrappings around the hips. Uneven shroudlike layerings give the appearance of several different hem lengths rather than one. Curious rectangular appendages swing from shoulders and bodices. An extra pair of sleeves, attached to the sides of a skirt, may either serve as a low-slung sash or hang free. Some clothes are punctured with holes, for what has been called the ''Swiss-cheese effect.''

As shoppers at the newly opened Manhattan boutique in SoHo are discovering, the clothes do work. Customers trying on the $535 Mongolian wool poncho are delighted to find that it looks great worn either frontward or backward, when the deep cowl neck turns into a hood. Men are intrigued by the oversized square-cut rayon shirts (from $140 to $185) and the hand-knit cotton-tape pullovers, despite their $225 price tags.

Graphic tights, printed with Japanese characters, are $25. Twenty-inch wool jersey gloves, which have flipperlike curves along the arm, cost $60. Some customers have been buying the intimate apparel (long nightshirts of cotton jersey, or satin pajamas - $105 for a top, $85 for pants) to wear on the street.

Japanese new wave designers such as Kawakubo are not like London's punk-inspired creators, with whom they have been compared. They are not making a social statement. Adapting technical skills and craftsmanship from their past to the present, they are exploring new, and possibly more modern, ways of dress.

Their experiments may seem bizarre, but to dismiss them out of hand would be a premature judgment. In any case, they are already having an impact. The textural richness of Japanese homespun tweeds is strongly affecting fabric design. Their black, gray, and white color palette has made its mark on mass-manufactured clothing. And designers elsewhere are looking to the East. Italy's Gianni Versace, for instance, says his new ready-to-wear collection is ''the Orient seen through Italian eyes.''