NATIONAL HARBOR, Md. - Eight contestants were named co-champions at the National Spelling Bee on Thursday night in an unprecedented competition that went to 20 rounds.

The eight finalists bested 565 other contestants ranging in age from 7 to 14 in the prime-time finals that ran past midnight. The result is the first time more than two co-champions were named and came as the Bee has become increasingly competitive, with contestants training with coaches and some parents paying to bypass the traditional path to compete.

The winners are: Rishik Gandhasri, 13, of California; Erin Howard, 14, of Alabama; Saketh Sundar, 13, of Maryland; Shruthika Padhy, 13, of New Jersey; Sohum Sukhatankar, 13, of Texas; Abhijay Kodali, 12, of Texas; Christopher Serrao, 13, of New Jersey and Rohan Raja, 13, of Texas.

The finalists were vying for the $50,000 prize in the finals that were broadcast nationally on ESPN.

Earlier in the day, after more than five and a half hours of intense competition, the field of finalists was reduced to 16 out of 50 young spellers.

The Bee, held at the Gaylord National Resort in National Harbor, Maryland, kicked off Tuesday. The contestants came from across the United States and several other countries, including Canada, Ghana and Jamaica.

As the clock crept past 11:30 p.m., Jacques Bailly, the Bee's longtime official pronouncer, made a remarkable declaration.

"Champion spellers," he intoned, "we are now in uncharted territory."

Calling the eight remaining contestants "the most phenomenal assemblage of spellers in the history of this storied competition," the longtime face of the Bee announced that, if no single winner could be crowned by the end of 20 rounds, all remaining competitors would be declared co-champions.

The announcement capped a day that showcased a level of excellence - and parity - unprecedented in the Bee's 94-year history.

The event has also become "ultracompetitive" partly due to a cottage industry that has built up in the increasingly fierce world of competitive spelling and a controversial new invitational program lets spellers bypass the traditional path to the national event, said Shalini Shankar, author of "Beeline: What Spelling Bees Reveal About Generation Z's New Path to Success."

"Every year they ramp up and get harder," she said, "because it's really hard to get these kids out."

The semifinals were scheduled to end by 2 p.m. but contestants proved more resilient than ever before. By 3 p.m., the Bee's organizers resorted to what Shankar called a "lawn mower" round of extremely hard words intended to winnow the remaining field. It worked, with spellers knocked out by head-spinning words such as Wundtian, coelogyne and yertchuk.

Sundar, already a four-year veteran of the Bee, made the finals after what he said was a physically taxing first half of the day.

"I was very tired, and I also did not drink a lot of water," the Clarksville, Maryland, middle schooler said. "Since it's going so fast, if you go to the bathroom you might miss your turn."

Much has changed since Bailly himself won the Bee in 1980.

Experts say many of the contestants who made it to the final 50 have personal coaches and spend practically every waking hour studying in preparation for this moment. The result is an unprecedented field of master spellers.

Another game-changing development is the new invitational program known as "RSVBee," now in its second year. In the past, spellers reached the national event only by winning a regional bee and securing a sponsor, often a newspaper, to cover expenses. But with the advent of RSVBee, which supplied 292 of this year's 565 contestants, families who can afford a $1,500 entry fee - plus six nights at the $300-a-night Gaylord and other expenses - can bypass the traditional path to the Bee.

"It's made the field balloon in an unprecedented way," Shankar said, and that pay-to-play model may "change the character of the Bee and who gets here." But she noted that even the kids who compete under the aegis of a sponsor typically have the help of a paid coach, "So it's rare that you see someone of really humble means making it here anymore."

Darian Douglas traveled farther than most of his fellow contestants. At 11, the Kingston, Jamaica, native was one of the youngest spellers to make the final 50. He won his country's national bee and was sponsored by his hometown paper, the Jamaica Gleaner. After correctly spelling back-to-back German-derived words - Kneippism and schlieren - he was knocked out by diallage, a dark green or bronze-colored laminated pyroxene common in certain igneous rocks.

Despite his young age, as Jamaica's national champion, he won't be eligible for the sponsorship next year. His parents, Tameka and Danian, said they're considering the RSVBee option but aren't sure they can afford it.

"I want to keep competing," Darian said, "but I don't think I'll be able to. Maybe I'll move on to other exploits."

This article was written by Orion Donovan-Smith, a reporter for The Washington Post.