In 1848, Richard Wagner had just completed the scoring for "Lohengrin" when the idea for a work on the Nibelung - dwarfs who owned a magic ring and a hoard of gold - began to crystallize.

Twenty-eight years later, he put the final touches on the score of "Der Ring des Nibelungen" ("The Ring of the Nibelungen"). It was a staggering accomplishment at the time and remains so today.Two major companies are about to meet the most difficult challenge in the world of opera - producing Wagner's Ring, 17 hours of music originally intended by Wagner to be performed over four days.

The Metropolitan Opera is performing the entire epic about love and greed and gods and goddesses three times in the next few weeks - the first time it has presented it in so short a span in 90 years. The Berlin Opera is bringing its version to Kennedy Center in June.

Both productions are selling out, as Wagner buffs from around the world scramble to attend one or both. At the Met, tickets for all four operas range from $60 to $620. Tickets at the Kennedy Center range from $120 to $380. The first cycle in Washington is June 2. The first Met cycle started April 1. All are being broadcast live on radio.

Wagner deliberately made his Ring inaccessible to most theaters of the day, and he created an opera house in Bayreuth, Germany, in 1876 to show the work.

"I no longer gave a thought to the Dresden or any other court theater in the world; my sole preoccupation was to produce something that should free me, once and for all, from this irrational subservience," the composer wrote in his autobiography.

Few companies perform the four works - "Das Rheingold," "Die Walkure," "Siegfried" and "Gotterdammerung" - in four days. Usually, the operas are seen singularly, or if produced as a cycle, are stretched out for weeks or months.

"Clearly Wagner knew what he was doing," said Speight Jenkins, general director of the Seattle Opera. "For the sake of the power of it, it needs to go the way it was meant to go." Seattle started an annual Ring cycle in 1975 but has not performed it for the past two seasons.

The Met's new production is the most traditional in the world. The rocky mountaintop where Brunnhilde, surrounded by a circle of fire, is put into a deep sleep by her father, Wotan, resembles a craggy peak. But the production departs from early traditional stagings by eliminating her horse and not having the Valkyries actually fly.

Berlin's Ring, new in 1985, is set in a futuristic tunnel designed by Peter Sykora. It was staged by Goetz Friedrich. Costumes are contemporary and punkish. In "Das Rheingold," for example, Alber-ich is clothed in a diving suit with air hoses. And Brunnhilde wears black leather and leather boots in the later operas.

"It's very modern. It is hot, especially with the lighting of the stage. But it looks quite snazzy," said Dame Gwyneth Jones, who sang Brunnhilde in Japan last fall.

"It shows the personal, psychological relationships between the persons in the Ring. It is a human Ring. It's not political at all," said Jesus Lopez-Cobos, general director of the Berlin Opera.

"The idea is that every end is a new beginning. At the beginning of the Ring you see a vision from the very end, and at the very end you see once more the first picture of `Rheingold.' It is life, going over and over."

At Bayreuth in 1976 to commemorate the 100th anniversary of the opera house Wagner built, Pierre Boulez conducted and Patrice Chereau staged the first Ring ever taped for television. The Chereau Ring is a comment on corruption brought by industrialization. Instead of three mermaids swimming around, "Rheingold" starts with three prostitutes near a hydroelectric dam.

In the Seattle production, Wotan is a stage director whose actors get out of hand. "It's the only untraditional cycle in America," Seattle's Jenkins said. "We try to be as mythic as possible. I think we follow very faithfully the words of the text and pay no attention to the stage instructions of Wagner." The San Francisco Opera is the only other American company performing a Ring.

Jenkins likes innovative approaches to staging the "Ring." So does Lopez-Cobos, who's conducting the first cycle in Washington. "Sometimes they go too far," Lopez-Cobos said. "I prefer to take the risk. You are sometimes inspired by new and interesting concepts on the stage."

Dame Gwyneth will sing Brunnhilde in the Met's third cycle. Next fall she'll sing in a Ring at the San Francisco Opera and in a new "Die Wal-kure" at Covent Garden. The Welsh soprano has sung in a lot of Rings, including the televised Bayreuth cycle.

Wagner's grandson, Wieland Wagner, made a fresh start at Bayreuth in 1951 - the first postwar Ring. With an almost barren stage, he stressed symbolism, thereby triggering today's interpretive productions.

Both the Met's and Berlin's current Rings replaced productions based on Wieland Wagner's. At the Met in 1975, the stage showed a ring shape - a giant, tilted, flat doughnut - with singers in costumes resembling dark choir robes. The lighting, mainly dark blue, set the psychological moods.

The shortest amount of time in which one could attend all four operas in that 1975 Met Ring production was six weeks.

James Levine, who conducts the Met's more traditional Ring, chose Otto Schenk to create the production and suggested Gunther Schneider-Siems-sen as set designer. "We knew Schenk would do something that was naturalistic, romantic and warm without any particularly strong external idea pushed onto the opera," Friend said.

New York cast members include Toni Kraemer and William Johns as Siegfried, Jessye Norman as Sieglinde, Gary Lakes as Siegmund, Christa Ludwig as Fricka and Waltraute and Matti Salminen as Hagen.

Brunnhildes in Washington will be Ute Vinzing and Anne Evans. Rene Kollo will sing Siegfried and Peter Hofmann will sing Siegmund. Wotan will be Robert Hale and Simon Estes, singing a cycle each.