Hanae Ichinose is a major character in the boarding house comedy Maison Ikkoku, where she resides in Room 1 of the aging apartment building called Ikkoku-kan. She is a short, middle-aged woman who lives with her young son, Kentaro, and her rarely-seen husband, a low-level salaryman whose presence is so infrequent that the other tenants are largely unaware of him until an unexpected layoff forces him to remain at home. Her physical appearance is unremarkable and somewhat squat, defined by her small stature and perpetually tousled brown hair. A notorious drinker who is rarely seen sober, Hanae’s personality is loud, boisterous, and fueled by a deep-seated love for gossip. She is an incurable busybody who delights in meddling in the lives of those around her, exploiting her room's strategic position near Ikkoku-kan's only communal telephone to eavesdrop on private conversations. When not drinking, her primary hobby is to spread rumors and stir up trouble, finding endless entertainment in the romantic trials of her fellow tenants, particularly the fraught relationship between the young manager Yusaku Godai and the beautiful widow Kyoko Otonashi.

Despite her habit of causing chaos, Hanae Ichinose is not a malevolent figure. Her motivations are a tangled mix of genuine, if misguided, affection and a selfish desire for amusement. She sees the younger Kyoko as a kind of "younger sister," willfully ignoring the significant difference in their ages, and frequently offers her advice. In many ways, she acts as a surrogate mother for Kyoko, even attempting to arrange an omiai (formal marriage interview) for her early in the story. However, her loyalty is fickle; she is just as likely to sabotage Godai's chances with Kyoko as she is to help them, often believing that the more affluent and stable Mitaka would be a superior match. Her interventions, even when born of good intentions, are almost guaranteed to backfire, leaving Godai and Kyoko in worse predicaments than before. Hanae’s primary role in the story is that of a catalyst and an obstacle. Alongside her fellow drinking buddies, the mysterious Yotsuya and the flirtatious Akemi, she forms a trio often referred to as the "loon squad" that constantly torments Godai. They frequently invade his room for raucous, late-night drinking parties where Hanae performs her signature drunken dance with Japanese fans, while Yotsuya performs bottle-balancing tricks and Akemi laughs. This constant interference, combined with her talent for spreading incomplete or incorrect information, ensures that Godai's path to winning Kyoko's heart is perpetually obstructed.

Hanae’s key relationships extend beyond her drinking circle. Her relationship with her son, Kentaro, is complex. She cares for him to the best of her limited ability, but she has no qualms about dragging him along to her parties or using him as an unwitting accomplice in her schemes to spy on Godai, much to the boy's profound embarrassment. Her marriage is also presented as a quirky union, which began not from romance but from a dubious drinking contest that Hanae won by cheating. Hanae experiences very little development or change over the course of the series. She remains a consistently comic and static figure, a force of nature whose core flaws persist from the beginning to the end. While she can demonstrate moments of surprising vulnerability, such as breaking down in tears when she believes Kyoko has moved away, these instances are fleeting and do not alter her fundamental nature. Her notable abilities lie entirely in her skills as a social nuisance. She has a remarkable talent for eavesdropping, an uncanny ability to organize parties in any location, and an encyclopedic knowledge of neighborhood gossip which she wields as a weapon for entertainment. The irony of her character is frequently highlighted by her name; Hanae means "flower branch," a poetic and beautiful name that shocks the other characters when they learn it, as it stands in stark contrast to her crude and messy demeanor.