U Profile: Age, Height, Origin, Career, Facts & More
As the trilingual Japanese rapper, lead dancer, and sub-vocalist of OURBIRTHDAY (아워벌스데이)—the seven-member multinational girl group launched under JYP Entertainment subsidiary INNIT Entertainment—U (유) brings international flair, inventive creativity, and hard-won survival show resilience to fifth-generation K-pop.
Long before taking the stage in August 2026 with OURBIRTHDAY’s debut single album Our Birthday, U won over Korean and global audiences through two major televised audition programs—SBS’s Universe Ticket and KBS2’s The Entertainer.
Thus proving her determination to turn a childhood dream in Japan into a thriving career in Seoul.
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Quick Fact List: U (유)
| Profile Category | Verified Details |
| Stage Name | U (유) |
| Former Stage Name | Yu (유우) |
| Birth Name | Kawasaki Yū (川崎 優) |
| Nickname | Yu-chan (유짱) |
| Group | OURBIRTHDAY (아워벌스데이 / OBD) |
| Agency | INNIT Entertainment (JYP Entertainment subsidiary) |
| Position(s) | Rapper, Lead Dancer, Sub-Vocalist |
| Birthday | August 21, 2008 |
| Age (as of Nov 2026) | 18 years old (International) |
| Zodiac Sign | Leo (Western) / Rat (Chinese) |
| Height | 158 cm (5’2″) |
| Blood Type | Not publicly disclosed |
| MBTI Type | INFJ (Previously INFP) |
| Nationality | Japanese |
| Hometown / Origin | Choshi, Chiba Prefecture, Japan |
| Dance Training | NEXTinDANCE (NiD) Academy, SONA Dance School |
| Debut Date | August 19, 2026 (Pre-debut unit “HUNGRY (Side B)” released July 29, 2026) |
| Representative Color | Carmine Brown |
| Representative Emoji | 🍮 (Pudding) |
| WHIP! Character / Avatar | TIRUMICO (티루미코) |
Early Life and Background
U was born Kawasaki Yū (川崎 優) on August 21, 2008, in Choshi, Chiba Prefecture, Japan, a coastal city located east of Tokyo. Her given name, Yū (優), translates to “kindness” or “gentleness” in Japanese—a fitting reflection of the warm, expressive nature she is known for today.
Growing up in Chiba alongside her parents and the family’s beloved pet dog, U developed an early fascination with music, dance, and personal styling.
Determined to build a strong technical foundation in performance, she trained at prominent Japanese dance academies, including NEXTinDANCE (NiD) Academy and SONA Dance School, exploring a wide range of dance styles before setting her sights on South Korea’s K-pop industry.
Beyond dance, U displayed remarkable linguistic aptitude from a young age: in addition to her native Japanese, she became fluent in both Korean and English, making her one of OURBIRTHDAY’s key multilingual communicators for international fans.
Making the leap from Japan to South Korea as a young teenager was an emotional milestone. U has shared that the very first time she boarded an airplane alone from Japan to Korea to pursue her idol dream, the reality of leaving home hit her mid-flight and moved her to tears.
Career Highlights
2023: First Survival Challenge on SBS’s Universe Ticket
U first introduced herself to global K-pop audiences in the summer of 2023 under her birth name, Yu (유우).
On July 13, 2023, she was unveiled as one of the 82 contestants competing on SBS’s global girl group audition program Universe Ticket—the survival show that ultimately formed the group UNIS—and participated in the show’s signal song release, “Come With Me? (Universe)”.
Despite competing against dozens of seasoned trainees at just 14 years old, Yu brought bright energy and sharp choreography to the early stages.
Although she was eliminated in Episode 4 during the second round, the broadcast gave her invaluable televised stage experience and sharpened her resolve to return stronger.
2024–2025: 3rd Place on KBS2’s The Entertainer and Signing with INNIT Entertainment
Rather than stepping back after Universe Ticket, U entered a second major audition program—KBS 2TV and JYP Entertainment founder J.Y. Park’s joint survival show The Entertainer (더 딴따라), which aired from late 2024 into January 2025.
Competing alongside future OURBIRTHDAY leader Cho Hyejin, Yu captivated judges and viewers with her expressive stage presence, multilingual charm, and rhythmic versatility.
By the finale of The Entertainer, Yu achieved third place overall, earning a coveted spot in the pre-debut project lineup DDDD 25. Immediately following the show’s conclusion, she officially signed an exclusive artist contract with INNIT Entertainment (an independent subsidiary of JYP Entertainment) on January 24, 2025.
While DDDD 25 was quietly shelved later in 2025 as INNIT Entertainment restructured its debut plans, U remained a core pillar of the label’s flagship rookie girl group project.
July–August 2026: Rebranding as “U”, “HUNGRY (Side B)”, and OURBIRTHDAY Debut
In July 2026, INNIT Entertainment began unveiling its first-ever seven-member girl group, OURBIRTHDAY—marking JYP Entertainment’s first new girl group project in four years following NMIXX.
On July 24–27, 2026, Kawasaki Yu was officially introduced to the public under her sleek new single-letter stage name, U (유), as part of the four-member “Side B” promotional unit alongside eldest member Kuk Chorok, vocalist Shin Hyewon, and maknae Kilala.
On July 29, 2026, the Side B unit released the pre-debut digital single “HUNGRY (Side B)”, showcasing U’s crisp rap cadence and agile footwork on Korean music broadcasts.
Less than a month later, on August 19, 2026, U officially debuted with the full seven-member lineup of OURBIRTHDAY, releasing their first single album Our Birthday (which peaked at #6 on South Korea’s Circle Album Chart and surpassed 123,000 copies sold) alongside the energetic “WHIP-HOP” title track “SQUEEZY”.
Brand Ambassadorships and Endorsements
Having officially debuted with OURBIRTHDAY in August 2026, U has not yet been appointed to any solo brand ambassadorships or individual commercial endorsements.
Throughout her initial promotional cycle in late 2026, U’s commercial appearances have centered on group-wide campaigns for OURBIRTHDAY—including promotional tie-ins for the 1st Single Album Our Birthday (distributed in partnership with INNIT Entertainment and Republic Records), Makestar fansign events, and major performance showcases.
Given her trilingual fluency across Japanese, Korean, and English as well as her DIY fashion sensibility, street-fashion, beauty, and global youth lifestyle partnerships are natural fits as the group expands into 2027.
Personality and Public Image
Testing as an INFJ (having previously tested as an INFP), U combines quiet introspection with vibrant emotional honesty. Bandmates and fans alike note that she is deeply expressive—wearing her heart on her sleeve and showing her genuine feelings more openly than almost anyone else in the group.
At the same time, she possesses an impressive inner calm: she loves practicing meditation and has a knack for tuning out chaos even in noisy backstage environments.
Within OURBIRTHDAY’s creative dynamic, U is celebrated as the group’s outside-the-box thinker. Her self-described specialty is coming up with unique, unexpected ideas that no one else has thought of—whether brainstorming choreography details, variety show bits, or visual concepts.
Inside the group’s shared dorm, she rooms with leader Cho Hyejin, eldest member Kuk Chorok, and fellow foreign-line member Achiraya, acting as a vital cultural and linguistic bridge between the Korean and international members.
Onstage, U’s compact 158 cm frame packs explosive precision and playful charisma. Represented by the rich, warm hue Carmine Brown, the pudding emoji (🍮), and her dessert avatar TIRUMICO, she brings a sweet yet punchy presence to OURBIRTHDAY’s hybrid pop-hip-hop sound.
Fun Facts and Trivia
- DIY Fashion Designer: Whenever U cannot find the exact style of clothing she wants in stores, she designs and customizes her own T-shirts by hand.
- First Public Recognition Story: U has shared that the very first time a member of the public recognized her on the job was a cleaning staff member at the filming venue of KBS2’s The Entertainer.
- Musical Inspirations: She is an avid fan of NewJeans and deeply admires Red Velvet’s Wendy for her vocal artistry.
- Idol Friendships: U maintains a close friendship with Ai, a member of the rookie girl group ERG.
- Lucky Charm & Favorite Season: She considers music itself to be her personal lucky charm and names Autumn as her favorite season of the year.
- Trilingual Talent: U is one of the most multilingual members of fifth-generation K-pop, speaking fluent Japanese, Korean, and English.
- Stage Name Evolution: During Universe Ticket (2023) and The Entertainer (2024–2025), she promoted under her given name Yu (유우) before adopting the stylized single-letter stage name U (유) for her 2026 debut in OURBIRTHDAY.
Social Media and Where to Follow
As of November 2026, U does not operate an individual public Instagram, TikTok, or X account.
Fans can follow her official photos, music show fancams, multilingual vlogs, and behind-the-scenes updates through OURBIRTHDAY’s official group channels managed by INNIT Entertainment:
- Instagram:
@ourbirthday_official - X (Twitter):
@OBD_offcl - TikTok:
@ourbirthday_official - YouTube:
@ourbirthday
Conclusion
U’s journey from a tearful solo flight out of Chiba, Japan, to the debut stage of OURBIRTHDAY is a story of grit, reinvention, and unmistakable charm.
After learning tough lessons on Universe Ticket, earning a podium finish on The Entertainer, and signing with INNIT Entertainment, Kawasaki Yu turned every setback into fuel for her 2026 debut.
Armed with trilingual fluency, razor-sharp dance instincts, and a creative mind that never stops inventing, U has quickly become one of OURBIRTHDAY’s most captivating and indispensable voices.
Want to explore the full group profile?
Back to the OURBIRTHDAY Members Profile Hub.