It was a wallop of rock and pop he never previously tasted. Sure, he's a biggie in Japan and a homegrown favorite, who just added another Na Hoku Hanohano Award (Best Instrumental Album) to his trophy shelf.

For Shimabukuro, 28, the Buffett appearances may be a ticket to mainstream stardom on the Mainland.

Shimabukuro, who also performed in an acoustic concert last night with Béla Fleck and the Flecktones, Jon-Luc Ponty and Stanley Clarke, at the Wolf Trap Foundation for the Performing Arts' Filene Center, says he's on cloud nine.

"I've always wanted to play Wolf Trap ... and all three guys were my heroes while I was growing up," he said.

But the exposure with Buffett, whom he met earlier this year when he joined the "Margaritaville" star on stage at the Waikiki Shell, "is priceless," said Shimabukuro. "My legs were shaking when I got on stage; I was so nervous. I looked straight at Jimmy and did not break eye contact. He knew how nervous I was, and he asked me, 'Are you ready?,' and I remember answering, 'I think so.' "

Though jittery, he did what he normally does: pluck and strum in a feverish, almost ritualistic dance with the uke. For the Buffett shows, however, the repertoire is not his, but Buffett's. Essentially, he's enhancing the Coral Reefer Band with his frisky ukemanship.

Shimabukuro got the nod to join Buffett after a member of the Coral Reefer Band, guitarist-singer Mac McAnally, gave Buffett a heads-up on how terrific Shimabukuro is. Buffett investigated — and agreed. That's how the Shell link started.

"I guess we were talking earlier in the week on Flag Day (Tuesday), and Jimmy asked me to open the concert with the national anthem," said Shimabukuro.

The crowd went wild. Shimabukuro appeared later in the first half, doing two songs with the band in the rock half of the show, then reappeared after intermission, to strum in an acoustic segment. "We kinda sit on a surfboard bench, in a more intimate situation," he said. "We only did his (Buffett's) songs, not mine. I returned for the final encore."

He relished one particular moment: "I know I held up the shaka sign, and thousands responded, doing the shaka, too. It was so cool."

Shimabukuro has nothing but praise for Buffett, whom he described as "a generous man, almost like an angel sent to me from heaven," he said. "I can't believe the opportunity we'll have, performing with him in five shows."

He said the pay's pretty good (he didn't reveal his wages) but in terms of exposure, "it's incredible. For me to reach that many people at once ... I'd have to be touring for a few years to graduate to that level," he said. Shimabukuro felt like a sophomore skipping to the senior level with the kind of impact the concerts are having on his career.

"The thing I find so wonderful about Jimmy is the way he is on stage is the way he is off stage," he said as an insider.

The show was physically exhaustive, but emotionally energizing, he said. "I mean, it's pure adrenaline; it's so exciting, and I'm learning so much," said Shimabukuro. "I could not sleep (Wednesday night after the show). I was so revved up, so pumped up, I was watching TV all night — reruns of 'The X-Files' — that I didn't go to bed till 5 a.m. I keep thinking about the whole, wonderful experience."

He next hooks up with Buffett in Boston, with another show June 26 in Pittsburgh.

The dates fit around Shimabukuro's earlier-scheduled performances with Fleck, a banjoist of note, with another Fleck gig June 25 in Bushkill, Pa.

He returns home for Fourth of July festivities at Gordon Biersch and Kapono's at Aloha Tower Marketplace, and has a whirlwind performance and appearance tour in Japan starting Aug. 15 to promote his just-released CD, "Dragon," which has been a brisk seller in Japan (30,000 since June 1). That album won't be available in Hawai'i till Aug. 2.