From Japan, we have:

Jonetsu Marie & Shabon High School (Marie and the Soap Bubble High School), a 1970's style retro pop music group from Kyoto that adds a lot of Kansai comedy and fun to its performances. They are really psyched for their performance at the Sakura Matsuri.
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Spirit + Noise combines traditional Japanese instruments such as the shamisen with modern Western instruments, including electric guitar and drums, to create a new genre of music that the group calls "Japanese junction." 
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Se-Shami Street presents a Japanese style street performance that will make everyone smile, notwithstanding  the language barrier.  This young and acrobatic group was formed while they attended Tsukuba University in Japan.  Using the Japanese traditional musical instrument called “shamisen”,  Se-Shami Street is ready to  introduce Japanese-style comedy to Washingtonians.   
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Tamagawa University Dance and Taiko Group, with its 34 young and energetic members, is back with us again, with another magnificently choreographed performance that is guaranteed to excite Sakura Matsuri visitors.  

ORIENTARHYTHM has created a completely new type of dance style, which combines Japanese martial arts with street dance and a bit of hip-hop flavor, too!
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From America we have:

Emi Meyer, the Japanese-American jazz singer.
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Shin Koyamada, who starred with Tom Cruise in “The Last Samurai” and in the Disney Channel’s “Wendy Wu: Homecoming Warrior”
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Reni Mimura, a Japanese cosplay singer whose Akihabara-style performances emphasize the cute look of Japanese pop culture and the hip appeal of Japanese animation.
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Yosakoi –Dance Project “10 Tecomai” is an incredibly dynamic Japanese dance group from New York City that will perform their high-energy fusion of both new and traditional Japanese dance.
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Uzuhi, a Japanese punk rock band from New York. Formed in 2004, “Uzuhi” means “the Sun” in Japanese.
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DJ Hayden Honey, the founder of Superglorious, has organized, produced and promoted numerous musical events featuring a diverse selection of major and underground Japanese artists.
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Other special guests:

Koichi Wakata, the Japanese astronaut who has been on four space shuttle missions and spent 4 ½ months aboard the international space station.

Maki Kaji, the man who gave sudoku its name and started the world sudoku craze.

President James Buchanan, who established diplomatic relations with Japan 150 years ago. (Courtesy of Madam Tussauds)
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Artisans and craftsmen, from doll-makers to carpenters to the bonsai experts of the National Arboretum, will be at the Festival to demonstrate and explain some of Japan’s greatest cultural traditions.