Koichi's Mother
- Primary work
- Diamond is Unbreakable
Koichi Hirose's Mother (広瀬 康一の母親, Hirose Kōichi no Hahaoya) is an unnamed tertiary character featured in the fourth part of the JoJo's Bizarre Adventure series, Diamond is Unbreakable.
She is the wife of Koichi's Father and the mother of Ayana Hirose and Koichi Hirose. She is tricked into believing Tamami Kobayashi 's lies about her son, causing her guilt to amplify due to Tamami's Stand, The Lock.

Image attribution details
Koichi's Mother. Source illustration via JoJoWiki; copyright remains with the original rights holders.
Image via JoJoWiki. Original franchise/production rights holders retain copyright; the wiki text CC BY-SA license does not license this image.
Original image ↗ · Archived image ↗01Basic information
02Appearance
Mrs. Hirose has dark, wavy hair styled as a pixie cut swept to the side. She has moderately thick eyebrows that are slightly arched upwards, and she is always seen with lipstick.↗
During her encounter with Tamami Kobayashi, she wears a striped blouse, a skirt, and slippers. The blouse's collar has a triangular brooch with a heart on it. When she goes shopping later on, she is wearing a long-sleeve blouse, a vest, and pants. She also has earrings on.↗
03Personality
Koichi's mother is a cheerful, lively woman. She is welcoming to visitors, seen being open to conversation with Tamami and defending him when Koichi rushes in. In general, she is cordial to strangers and gets along with them well.↗↗↗
She can be somewhat gullible as she believes what Tamami tells her, even when he has to correct a lie about talking to someone with a broken jaw. Although initially succumbing to his manipulation to the point of wanting to commit suicide, her love for her son, who she affectionately calls "Ko-chan," triumphs. In her heart, she trusts her son over anyone.↗↗↗
04Story
SPOILERS
Background
After getting married to Koichi's Father, they have their first child, Ayana, in around 1981. In 1984, they have their second child, Koichi. At some point, they adopt a dog into the family named Police.↗
Koichi Hirose (Echoes)
Mrs. Hirose is greeted by Tamami, who makes up a story about how he kindly found the 7,000 yen that her son dropped and wanted to bring it back to him. She lets him into her house while they wait for Koichi to come home from school. As Koichi returns, he finds Tamami massaging his mother's shoulders and praising her with fake compliments.↗
Tamami claims that when Koichi bumped into him with his bicycle, they accidentally exchanged wallets and that his contained over 500,000 yen. Tamami adds weight to his accusation by commenting that the wallet in Koichi's possession contains a bill from a dinner he had the night before, and to Koichi and his mother's surprise, the bill is indeed in the wallet.↗↗↗
After a loud scream from Tamami, she runs back into the room to find him bleeding with the knife in Koichi's hand. Unaware that Tamami had actually cut himself in order to frame Koichi, The Lock on Mrs. Hirose's chest multiplies in size due to her guilt. Koichi's mother cannot bear her guilt and takes out a knife, preparing to stab herself with it. Tamami orders Koichi one last time to stop the sound, but he answers that he won't stop, but emit another sound.↗↗
Yukako Yamagishi Dreams of Cinderella
Mrs. Hirose and Ayana are out shopping when they stumble upon Koichi and Rohan. Surprised to meet a famous manga artist, she calls him handsome and requests to come with them to Kameyu Market. Yukako is frustrated that of all people, Koichi's mother had to show up because she had hoped to be alone with Koichi. They also meet up with Josuke and Joseph along the way. While at the store, the flash of Rohan's camera startles Shizuka.↗↗
Highway Star
Mrs. Hirose tells Koichi to take their dog Police for a walk. Before he leaves, their phone starts ringing and she yells at Koichi to answer it because she's in the bathroom.↗↗
Goodbye, Morioh - The Golden Heart
In the anime adaptation, she and Ayana are outside Kameyu when Ayana tells her that she just saw Koichi holding hands with a really pretty girl. Mrs. Hirose is shocked because Koichi never told her anything.↗↗
05Plot details
SPOILERS
Profile details
Status Status based on their final appearance in the part(s) they are featured in: Alive (Part 4)↗
06Appearances
07Relationships
| Character | Relationship | Notes |
|---|---|---|
| Ayana Hirose | Daughter | ↗ |
| Koichi Hirose | Son | ↗ |
| Police | Pet | ↗ |
08Sources & attribution
- Koichi's Mother
Source bibliography (8)
- Artbook: JoJo 6251 Open ↗
- JOJO magazine 2024 WINTER: Women in JoJo Open ↗
- Chapter 286: Koichi Hirose (Echoes), Part 3 Open ↗
- Chapter 351: Yukako Yamagishi Dreams of Cinderella, Part 4 Open ↗
- Chapter 288: Koichi Hirose (Echoes), Part 5 Open ↗
- Chapter 287: Koichi Hirose (Echoes), Part 4 Open ↗
- Chapter 388: Highway Star, Part 5 Open ↗
- Diamond is Unbreakable Episode 39: Goodbye, Morioh - The Golden Heart Open ↗
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