Jimmy Yagi, the architect of “Vulcan Fever” who put Hawaii’s small college basketball on the map with energy, tenacity and, most of all, humility, died Wednesday of natural causes at Hilo Medical Center.

He was 88.

“Jimmy took his last breath this morning and died peacefully,” his wife, Jeanne, said in a text message, noting that their sons Kirby and Brady were also at Yagi’s bedside.

Yagi would have never said this himself, but the upset victories and sustained excellence by his Hawaii Hilo teams in the 1970s set the stage for the more nationally known Chaminade victory over Virginia in 1982 and Hawaii Pacific’s 1993 Division II national championship.

“Give them credit,” said Mark Rodrigues, a ferocious competitor who played against Hilo and Virginia as Chaminade’s starting point guard. “He’s the one who brought small college basketball to the forefront. They were what Chaminade envisioned to be, they were the standard. Then after what we did, Hawaii Pacific became a very good program.”

Hilo athletic director Ramon Goya was also instrumental in building the Vulcan program so that it could play a college-only schedule — and dominate it from the start, going 50-8 in Hilo’s first two years in the NAIA.

In UH Hilo’s first NAIA season of 1976-77, Yagi and the Vulcans upset Division I teams Nebraska and New Mexico before winning the district championship and playing in the NAIA national tournament.

Hilo went 23-3 that year, and 27-5 the next; both teams reached the second round of the national tournament which was then held in Kansas City every year.

“I wouldn’t say it was surprising,” said Yagi, in a 2017 story on the UH Hilo website, a few days before he and the 1977 team were inducted into the Vulcan Athletic Hall of Fame. “It was more of a shock. It was so incredible that it took a long time to comprehend how it happened.”

In 1977, the Vulcans beat Spring Garden. Then they lost to Illinois Wesleyan, which was led by future NBA Hall of Famer Jack Sikma.

The following year, Hilo beat Franklin (Ind.) before losing to Grand Canyon, which went on to win the championship.

The Vulcans home games were sellouts at the Hilo Civic, and five of them were televised statewide. “Vulcan Fever” was among the state’s biggest sports stories of the 1970s, and their fan base extended from the Big Island to Oahu and beyond.

“He is the grandfather of small college basketball in Hawaii and his early Vulcan teams set the standard for schools like Chaminade, Hawaii Pacific and BYU-Hawaii to follow in developing strong programs that could compete nationally at the NAIA and NCAA Division II levels,” said Bill O’Rear, a star guard on Yagi’s early teams who later became one of his assistant coaches, and a lifelong friend.

O’Rear became the sports editor of the Hawaii Tribune-Herald, and worked statewide youth camps with Yagi for 30 years.

“Coach Yagi is the best person I’ve ever met — kind, selfless and willing to help anyone who reached out to him,” O’Rear said. “He loved his players and used a high-energy, positive coaching style to inspire his teams and get the most out of them.”

UH Hilo’s 81-78 victory in 1976 over New Mexico, a team led by future NBA standout Michael Cooper, was the Vulcans biggest upset win. But it was a 164-111 loss to Jerry Tarkanian’s UNLV team in 1976 that got them into the College Basketball Hall of Fame.

National scoring records were set in that game, so the ball was sent to the Hall of Fame

Alan Tanabe, a 5-foot-10 freshman from Hilo High, scored 30 points to lead the Vulcans. (Future NBA star Reggie Theus scored 16 for the Rebels.)

“We gave up 164 points, but the Vulcan fans gave us a standing ovation,” Yagi said after the game. “And if Alan Tanabe was allowed to run for mayor after that performance he would have gotten elected.”

In 18 seasons, Yagi’s teams won three district titles. His record in 12 NAIA seasons was 218-87.

But his legacy includes much more than the college wins and losses. Yagi impacted countless kids at his camps. They included Daphne Honma, the vice principal at Honokaa High and former UH Hilo women’s coach, who was 12 when she first attended the Vulcans camp.

“For me, coach Yagi has been my mentor, my basketball father figure,” Honma said. “I really learned a lot from him, not just basketball, but life skills. He reached even the little ones and always made it fun. He stressed being on time, but having fun, too. As you get into competition, yeah, you gotta be intense, but he always said you can be intense and have fun, too.”

Yagi was born and raised in Hilo, graduated from Hilo High and lived most of his life there.

Services are pending.