What happened
Hinatazaka46 (an idol group, a pop act whose members are marketed individually to fans) premiered the music video for 'Enshuritsu' (Pi) on its official YouTube channel on May 18 at 10 PM JST (Japan Standard Time). The song is a track by the group's 5th generation — its newest cohort of members — and appears on the group's 17th single, 'Kind of love,' released May 20. The concept is unusual: the song is themed around pi, the mathematical constant.
Director Yoshida Yuki said he wanted to capture the value of seemingly 'wasted' youthful time — goofing off and taking detours — in an era obsessed with efficiency.
Why it is trending now
The headline reason is that Sato Yu takes the center position for the first time in a 5th-generation song. In Japanese idol groups, the center is the most prominent spot in a formation, so a member's first center is treated as a milestone, and the formation reveal set off celebratory posts. The choreography added a second hook: it is playfully built around the shape of pi and the digits 3.14, a detail the choreographer highlighted directly.
How fans reacted
Reaction skewed strongly positive. Fans celebrated Sato Yu's debut as center, praised individual members frame by frame, and enjoyed the math puns woven into the dance. The live-premiere format turned it into a shared watch-along, amplifying the buzz on X.
What to watch next:
Attention now turns to the 5th-generation solo live on July 15-16 at Pia Arena MM in Yokohama, announced alongside the MV. It will be the cohort's third standalone performance, and ticket demand and the set list will be the next things fans track.




日向坂46五期生曲「円周率」ミュージックビデオを今夜プレミア公開、最後まで目が離せない #日向坂46_円周率 #日向坂46
☀️MVプレミア公開☀️ ⚠️今夜5/18(月)この後22:00 日向坂46 17th Single収録 五期生楽曲『円周率』MVがプレミア公開されます✨ みんなで一緒に視聴して盛り上げましょう🙌 チャット&コメントで感想大会! ぜひ最後までお見逃しなく! 🎬 #日向坂46_円周率 #️⃣日向坂広報部
2:17みーちゃんがかわいすぎる😭😭😭 #日向坂46_円周率
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