Genjibu’s Ooura Kūto and Nagano Ryouta Talk Tetsunabe no Jan! OP ‘Kaen’ – Choreography Includes a Cutting Board?

The anime adaptation of Saijou Shinji’s cooking manga Tetsunabe no Jan! began airing on July 5 on TV Tokyo and other networks. The opening theme is performed by the seven-member dance vocal group Genjibu (原因は自分にある。), known for their diverse creative activities beyond typical idol boundaries. The group drew 20,000 fans to a two-day live at Yoyogi National Stadium First Gymnasium in July 2025, and recently completed their first arena tour across Tokyo and Kobe with six shows and 50,000 attendees.

Live-Ready Track and a Chinese Restaurant MV

――What are your impressions of the new opening theme “Kaen”?

Ooura Kūto: The sound and lyrics clearly express the world of Tetsunabe no Jan!, but my first impression was that this is definitely a song that will get the crowd hyped at live shows! I think it turned into a track that lights a fire in the hearts of not only our fans (called “Kansokusha”) but also a wide range of generations.

Nagano Ryouta: It has a sense of speed that feels very Genjibu—never straightforward—and I think it inherits the world of Tetsunabe no Jan!, where logic and madness mix.

――Which lyrics stand out to you?

Ooura: I really love the chorus line “Dakyou nante nashi, kore ga ore no stance” (No compromise, this is my stance). It conveys a strong will to never cut corners and go all out to the end. And the fact that it’s sung by the stoic Mukudai Kazuto makes it the best assignment for me!

Nagano: The line I sing, “Yuragu yami no naka hi o tomose, fusagaru ashita mo ima kojiake” (Light a fire in the wavering darkness, pry open the blocked tomorrow), feels very Genjibu—turning negatives into positives—and I like it.

――Any highlights in the MV, choreography, or costumes?

Ooura: In the intro, the choreography has us make a knife with the right hand and a cutting board with the left. It’s really catchy, and I hope everyone will try copying it!

Nagano: The MV is a comedic departure from our usual style—it shows us working part-time at a Chinese restaurant. That’s the point to watch for.

――What did you think of the manga and anime?

Ooura: I found it fascinating how the protagonist Jan has overwhelming confidence backed by real skill, and how he experiences setbacks and growth through his first rival. I was shocked when Jan made chawanmushi using sheep brains. I’d like to try it once.

Nagano: Unlike ordinary manga or anime, the appearance of bizarre dishes is a really unique perspective. I love shrimp chili, so I’m curious about the “umasa 300 bai, noukou ebi miso ebi chili” that appears in the story (laughs).

――Which character do you relate to?

Ooura: Akiyama Kaiichirou, the King of Chinese Cuisine. The pride in the name “Akiyama,” and the way he drills his skills into Jan using old-school methods—that’s worthy of a king. I also love his exit when he realizes his own tongue has gone wrong. The depiction of his lingering love for Jan despite having no regrets as a chef was wonderfully clumsy.

Nagano: The protagonist Jan. He’ll use any means to defeat an opponent—he’s quite punchy. But I also try to absorb various things every day for Genjibu and our dreams, so I feel we share a fundamental obsession with winning and seeing things through.

――Characters have mottos like “Cooking is heart,” “Cooking is a match,” “Cooking is hearty.” What is “Cooking is _____” for you?

Ooura: “Cooking is love.” Our vocal trainer, Ryonryon-sensei, often makes onigiri and soup for us, and they’re really delicious! When I asked why, she said it’s because she puts love into them. I think that’s exactly right.

Nagano: For me, cooking is juicy. I like any food that’s juicy and well-seasoned. I rarely cook, but the only things I can make are omurice and tomato pasta. My specialty is making them saltier than usual.

Genjibu’s Chinese Connection?

――You’ve all gone to Chinatown together. Any favorite Chinese dish?

Ooura: My favorite is gyoza. I love many Chinese foods (xiaolongbao, shumai, spring rolls, fried rice, ramen, shrimp chili, mapo tofu), but my mother’s gyoza is especially delicious! She makes a huge batch for our family of four, and I always finish it all.

Nagano: I love Chinese food so much it’s hard to pick just one, but lately I’ve been into an-kake chahan (sauce-topped fried rice).

――Member Koizumi Mitsuaki is a huge ramen fan who even makes noodles from scratch. What Chinese dish would you like to master?

Ooura: Spring rolls. When I first started living alone, I invited Koizumi over and spent two to three hours making spring rolls. He patiently waited and said they were really delicious, so I’d like to perfect them!

Nagano: I’d love to be able to make chinjao rosu (green pepper and beef stir-fry) myself. I’ve loved it since I was a kid.

――You often eat together. Who did you recently eat with and what?

Ooura: Koizumi, Sakuragi Masaya, and I sometimes go on ramen trips. Koizumi recommends the shops, and Sakuragi drives. Everything is amazing. Our next trip is planned for mid-July. I’m the navigator in the passenger seat.

Nagano: Recently I had curry udon with Ooura, and teppanyaki with Yoshizawa Yōto. My current food recommendations are bibimbap and cold noodles.

Anime They Love

――Do you watch much anime? Any recent favorites or all-time classics?

Ooura: I love anime and manga. When I get into a series, I rewatch it so many times I memorize the key scenes. I’m especially a huge fan of Hunter × Hunter. Recently I finished Summer Time Rendering and am now reading Ushio to Tora.

Nagano: I love anime. My all-time favorites are Neon Genesis Evangelion, Steins;Gate, and Sonny Boy. Lately I’ve been catching up on series I paused, like FLCL and the Monogatari series.

――A message for viewers, new fans, and your Kansokusha?

Ooura: I’ve been influenced by manga and anime since I was a kid, so I’m really happy to be in charge of the theme song and help energize Tetsunabe no Jan! I think we can make both original fans and our Kansokusha happy. Please look forward to the anime broadcast and the song release!

Nagano: I’m very fortunate to be involved with a long-loved work like Tetsunabe no Jan! This opportunity is thanks to our Kansokusha who always support us. I hope anime viewers will discover even more charm in the series, and if that leads them to check us out, I’d be honored. See you at the live venues!

【Release Information】
Artist: 原因は自分にある。
Title: 火宴 (Kaen)
Release date: July 6, 2026