J. Kai Yamafuji made Hawaii pole vault history last week, and there’s a good chance his gravity-defying exploits will go on unabated for a while.

Locked in an intense duel with ‘Iolani’s Logan Rubasch at the ILH championships on Wednesday, the Punahou sophomore dug deep to come out victorious and wound up becoming the first person in Hawaii to clear 16 feet.

But he may have just begun to tap his potential, according to coach and former Olympian Tom Hintnaus.

“He made 16 by 4 to 5 inches and he was nowhere near vaulting perfect,” Hintnaus said at the Kamehameha track after Yamafuji’s vault Wednesday. “I think he can go 16-6 (at the May 11-12 state meet). But if he goes 16 feet, I’ll be happy. I’ll be happy with a win at any height.”

Hintnaus had a good laugh after the comment, realizing that a few hours earlier, saying such a thing wouldn’t have made sense. At that time, Yamafuji’s personal best was 15-5, a Punahou Relays record set April 21.

In addition, Yamafuji was up against Rubasch, the senior who beat Yamafuji at both the ILH and state meets a year ago. And on Wednesday, Rubasch drew first blood by setting an ILH meet record of 15-3 on his first try. Yamafuji made matters even worse for himself by missing on his first try at that height. But, later on, he successfully soared to 15-9 and then 16-0.

Since first trying pole vaulting in seventh grade, Yamafuji — with his now graceful runs down the track leading to those powerful vaults — has come a long, long way.

Hintnaus goes as far as saying “awful” and “clumsy,” words that — if Yamafuji reads them and takes them to heart — may further fire him up to clear at least another inch some day.

“In seventh grade, he would run to the right and almost miss the pit every time,” the coach said. “After eighth grade, I said, ‘Do you want to do this?’ Do you want to learn how to go straight?’ I told him to overexaggerate, go to the left side, the left side. With the power and speed he had, in ninth grade he made a 5-foot improvement and made 15 feet at the state meet. (Rubasch also reached 15 and placed first due to fewer misses.)

“This year, he’s been knocking on the door every week. He got 15-1 the first week, 15-2 the second week, 15-3 the third and so on. I told him, ‘If you put one together and you really do things right, you can make 16 feet,’ and he did it.”

Yamafuji admittedly did not do well in the more traditional sports when he was younger.

“In middle school, I tried pole vault and it was really fun and so different than anything else,” Yamafuji said. “It’s also different than anything else in track and field. It’s not technically a jump. It’s its own thing.

“At first, I was very, very bad in it. I pretty much no-heighted at 5 feet until the last meet in seventh grade, when I made 9-6. After that I did better and got a PR of 10 feet, but I was bummed that I lost the intermediate championship on number of attempts. For some reason, Coach Tom saw the potential in me. I don’t know why. I had absolutely no form. Nothing.”

Yamafuji would like to compete in college some day, but is in no hurry to get there. He is enjoying his time at Punahou, and he has slightly more than two years to set the Hawaii bar even higher.

“One of my hobbies is looking at college track and field rosters to see what their guys are doing,” he said. “I look at their all-time top-10 list and see where I can possibly be if I go to that college. All of it is amazing. Some of the schools, the top guys are at 18 feet. I see places where I know I can compete, and I say, ‘This is where I am now. Where do I want to be?’ ”

It’s not out of the question that Yamafuji could, like Hintnaus, try for the Olympics some day.

“It’s every track and field kid’s dream,” he said. “For now, I’ll focus on trying to get into college.”

For fun, Yamafuji tried the triple jump this year and qualified for states in his first competition.

“Pole vaulting is my first priority,” Yamafuji said.

Last year, Yamafuji’s 15-0 ranked fourth in the nation among freshmen. This year, his 16-0 is unofficially second in the country so far among sophomores. He keeps track of that stuff, and he’s enjoying his incremental rise. He also recently learned something the hard way.

“A few weeks ago at the Cal Track Ruby Tuesday meet, I was thinking, ‘This is my chance to show off. There are a lot of people here.’ My first attempt at 14-0, I ran through and smashed my pole on my face and it gave me a mark on my forehead. It was pretty funny. Some day, I will tell my kids, ‘Don’t try to show off. Just do what you know how to do.’ ”