Tsurumaki Kokoro is a happy-go-lucky first-year student at Hanasakigawa Girls' High School and the leader and vocalist of Hello, Happy World!.

Her goal in life is to make the entire world smile. Her family is super rich and lives in one of the biggest houses around the area.

In the second season of the anime, she is a second-year student.


Kokoro has large, rounded yellow eyes and long, straight, waist-length platinum blonde hair. Her fringe is cut unevenly and separated into two parts. She has thin forelocks which touch her shoulders.

Her casual attire consists of a red and white striped t-shirt with fluttery sleeves, blue denim overalls, and a hair tie with red ribbons on her wrist.


An idealistic and charismatic young girl coming from a ridiculously rich family, Kokoro dreams of making the entire world smile from music. She effortlessly attracts others to her due to her bright and bubbly nature, and often manages to get them swept up into her easygoing pace. Because of her charismatic and naturally imposing personality, she is often able to do and get what she wants. She is also extremely curious and easily amazed, charmed by new things she discovers in the world around her.

Although Kokoro has the optimism and charm of a natural leader, she is also quite scatterbrained and ditzy, and would not be able to get much done without the others in the group helping her. She also has said that she doesn't know what it feels like to be sad, and does always her best to combat any kind of negative feelings.

Game Interactions

A list of characters Kokoro interacts with in the game.

Kaoru (icon)Hagumi (icon)Kanon (icon)Misaki (icon)Kasumi (icon)Arisa (icon)Tomoe (icon)Hina (icon)Eve (icon)Sayo (icon)Lisa (icon)Rinko (icon)


  • She is the only character in the series who refers to everyone (including Marina) with their first names and without using honorifics.
  • Kokoro thinks reading, especially reading picture books is fun and often loans them from the library.
  • Along with Hina, she also joins the Astronomy club in her own school in the event Searching For Stars, so they are pretty close to each other.
  • Kokoro mentions in one of her summer dialogues that her family own a private beach, and in another one of her autumn dialogues, that they also own a mountain.
  • Some fan theories say that Kokoro is a genius but doesn't realize it.
    • In one of the 1-panel comics it was shown that Kokoro instantly learned how to ride a horse, which explains the theory.
  • Another fan theory is, that Kokoro's family is rich because her dad is part of the Yakuza.
  • Her body is very nimble and such she is able to do backflips even while wearing a furisode.
  • Kokoro is hyper and acrobatic that usually only the black-suited people - her three bodyguards - can manage to stop her.


Card Name Rarity Type Skill Availability (Initial Availability for permanent gacha cards)
Hanasakigawa Dimension 1★ Happy Score Up Band Story 1 Chapter 1
Onstage 2★ Pure Perfect Lock + Score Up
Invincible Hero 3★ Power Score Up
Sakura Special! 3★ Pure Score Up Hanasakigawa's Sakura Gacha
Maritime Detective 4★ Happy Score Up Detective Kokoro Gacha
Garupa Cafe♪2017 2★ Happy Life Recovery + Score Up Garupa Cafe♪2017 Campaign
Lawson Collab 2017 2★ Power Score Up Lawson Collab 2017
A Happy Revolution! 3★ Happy Life Recovery + Score Up Hello, My Happy World
Bang! On the Scene 2★ Pure Score Up Bandori 1st Election Commemoration
Apprentice Witch 4★ Power Score Up One Night Magic Limited Gacha
Poppin' & After 2★ Cool Life Recovery + Score Up Someday, A Poem For You: Lisa's Lyrics
I'm a Penguin Too! 2★ Power Life Recovery + Score Up Frozen Aurora Gacha
New Year's is Full of Fun 4★ Pure Life Recovery + Score Up Springtime Sunrise Limited Gacha
The Magic of Smiles 2★ Happy Perfect Lock + Score Up
Here We Go, Guys! 3★ Cool Life Recovery + Score Up Backstage Pass
I Love Fluffy Mascots! 2★ Cool Score Up Fair and Square! Fluffy Character Championship
Rainy But Sunny 4★ Cool Life Dependent Score Up Roaring Rimshot Gacha
Smiling Tryst 2★ Pure Life Recovery + Score Up On Sunday, We Got Separated At The Park
Thrilling Discovery 3★ Pure Life Dependent Score Up Exciting! Tropical Adventure Gacha
Fish Competition 2★ Power Perfect Lock + Score Up Flash! SUMMER DIVE
Sparkling Sun 4★ Power Life Dependent Score Up Make The World Smile! Smile Parade Gacha
An Exciting Strategy Conference 3★ Power Perfect Lock + Score Up Twin Star Ensemble
Pop-up Picture Book 3★ Cool Perfect Lock + Score Up Sleeping Blue Sheep Gacha


Poppin'Party Toyama KasumiHanazono TaeUshigome RimiYamabuki SaayaIchigaya Arisa
Afterglow Mitake RanAoba MocaUehara HimariUdagawa TomoeHazawa Tsugumi
Pastel✽Palettes Maruyama AyaHikawa HinaShirasagi ChisatoYamato MayaWakamiya Eve
Roselia Minato YukinaHikawa SayoImai LisaUdagawa AkoShirokane Rinko
Hello, Happy World! Tsurumaki KokoroSeta KaoruKitazawa HagumiMatsubara KanonOkusawa MisakiMichelle
RAISE A SUILEN Wakana Rei/LAYERNyubara Reona/PAREOSato Masuki/MASKINGAsahi Rokka/LOCKTamade Chiyu/CHU²
Glitter☆Green Ushigome YuriUzawa RiiWanibe NananaNijikki Hinako
ARGONAVIS Nanahoshi RenGoryou YuutoMatoba WataruShiroishi BanriKikyou Rio
Others Tsuzuki ShifuneTsukishima MarinaToyama AsukaUmino Natsuki