ALMOST one year ago, Yasumasa Mori clambered into a magnificently spangled white nylon jumpsuit, savagely back-combed his hair and lurched nervously on to the stage at Bad Bob's Vapours Club in Memphis, Tennessee. The performance he gave that night crowned him as the Elvis Presley Impersonation Champion of the World, king for a year and, in his case, a man with a mission for life. As the first non-American to win the world's most revered Elvis contest, Mori-san must have something, because there is plenty he doesn't have. There are no luxurious swooping sideburns, no greased back hair, no lustrous blue eyes, nor the flawless dentistry that all the other aspiring Elvii (the accepted plural) were flaunting in the backstage dressing rooms that night at Bad Bob's. It seemed churlish to ask how a skinny, ex-trading company junior manager from Tokyo beat dozens of genuine lookalikes in imitating the famous hip shaker from Tupelo, Mississippi. But I didn't need to ask. ''I know I don't sound much like Elvis. I certainly don't look like him, but the big Elvis fans chose me because I sing from the bottom of my heart,'' he volunteered. All was made clear from a video tape of Mori-san's winning performance. As the rank outsider from the Orient ventured out on to the stage, weighed down with rhinestones and jewels the size of ping pong balls, the audience of several hundred middle-aged Tennessee dames (officially known as ''Elvis Widows'') nudged each other in disbelief. Apparently unperturbed, our 31-year-old hero launched himself into a roistering rendition of ''Blue Suede Shoes''. Suddenly the background twittering fell silent and the ladies sat up like a pack of hyenas alerted to luscious new prey. Dame Edna spectacles were perched on powdered noses and shoulders began to twitch. Mori-san flung on a swirling A-line tasselled cape and plunged into Hound Dog. He is lithe as a whip and has a terrific line in hip swivelling. The Elvis Widows were euphoric. They fell about, leaping up from their chairs for the hot numbers and quietly swooning in the slow ones. At the end, Mori-san scampered off backstage, his brow agleam with sweat and with micro seconds to spare as hundreds of moist-lipped ladies lunged out on to the stage, clawing hands outstretched and bosoms heaving. Mori-san has come a long way from his humble early homage to The King. ''I used to be an ordinary kind of Japanese guy and ordinary Japanese guys just do not shake it. But then I learnt to move and I knew Elvis was in my reach.'' In his early incarnation as a rock'n'roll singer in the Lollipop Club in Tokyo, Mori-san's repertoire included a few Presley hits, but his early grapplings with the Elvis role were severely hindered by language difficulties. Fortunately, on one of his fact finding missions to Memphis, he met the Canadian daughter of an Elvis Widow, herself also a passionate devotee of the cult of Elvis, who married him and began shaping him as the future King. There followed a long haul of serious training. Like a Japanese sushi chef who trains for two years just to learn how to boil his rice and another eight to master fish slicing and preparation skills, Mori-san put in 12 years of dedicated study. He also amassed a heap of white nylon romper suits lovingly sewn with jewels and Elvis insignia, which he maintains with a dedication that verges on the sacramental. His tiny Tokyo apartment has Elvis memorabilia pinned on everything you can stick a pin into. When he hands over his crown next month to the new world Elvis champion, Mori-san will not be hanging up his spangled jumpsuits to go back to Lollipop Club rock'n'roll standards. He has a mission to keep the Elvis name alive in Japan. Concerned that the average Japanese man on the street barely knows Elvis from his elbow, Mori-san plans to train a new generation of young Japanese in the fine arts of Elvis impersonation. ''I'm going to stick with being a professional Elvis impersonator. My goal is to teach Japan how great Elvis really was. My chosen task is serious and difficult, but I believe I can succeed.''