OSAJI: From Masakazu Shigeta’s Cosmetics-Making to a Brand Connecting Fragrance, Everyday Life, and Memory

The fragrance I want is not always the same. It is natural for it to change.
Masakazu Shigeta — Founder and Brand Director of OSAJI

Opening a window in the morning. Washing your hands. Choosing what to wear today. These are the everyday acts beside which OSAJI seeks to place fragrance. Beginning with skincare that cares for the skin, the brand has extended its thinking beyond perfume worn on the body to the experience of blending a scent for one’s own home and objects that bring fragrance into every wash.

For founder Masakazu Shigeta, making things began with creating cosmetics that someone close to him could use. That experience, and his respect for the sensibility of the person choosing a fragrance, are also expressed in the eaux de toilette renewed in 2025. For their names, he chose not flowers or people but “prepositions.” These small words indicating time, place, and relationships between people were intended to connect fragrance and memory.

Key Facts
The Founder and the Origins of the Brand
The Brand’s Approach
References

Key Facts

Brand founded: 2017
Founder: Masakazu Shigeta
Origins: Developed from the cosmetics business of Nitto Denka Kogyo in Takasaki, Gunma Prefecture; spun off as OSAJI Inc. in 2023
First perfume: Eau de toilette launched in 2020
Official website: OSAJI

The Founder and the Origins of the Brand

From His Mother’s Skin Concerns to Kitchen Experiments

Shigeta worked as a recording engineer in the music industry. At a time when methods of recording and distribution were changing, he considered starting a different business and founded a package-design company with two friends. Through working with cosmetics and health-food clients, he became interested not only in designing containers but also in proposing what went inside them.

Meanwhile, his mother’s skin concerns prompted him to learn about cosmetics themselves. She preferred naturally derived cosmetics, but her skin changed and products she had previously used no longer suited her. This could not be explained by the idea that “if something is edible, it must also be good for the skin.”

Around 2001, Shigeta began experimenting with cosmetics in his kitchen at home and studying dermatology and formulation. His mother’s suggestion that, as a good cook, he might also be able to make cosmetics was another starting point. Combining ingredients for someone close to him became his first step toward a career as a cosmetics developer.

Turning Trust in Plants into an Examination of Formulations

What Shigeta questioned was not the use of plants itself, but the idea that the words “plant-derived” alone could guarantee compatibility with the skin. Even an edible yam can cause irritation when it touches the skin. The lacquer tree offers another example from the plant world. The impression a material gives needed to be distinguished from its properties when used on the skin.

Learning from his uncle, a dermatology researcher, Shigeta pursued product-making informed by the skin’s structure and functions. In a 2019 conversation with Taeko Kusaba, he recalled once describing himself as “anti-organic,” while also discussing the possibility of using plant ingredients in formulations designed with sensitive skin in mind. Rather than selecting materials by their origins alone, he would build products around the people using them. That approach became OSAJI’s foundation.

From Commercialization in 2004 to OSAJI in 2017

His early work included developing cosmetics for inns around the minerals in hot-spring water. He came to want not merely to outsource manufacturing, but to carry out analysis and production himself. The family business, Nitto Denka Kogyo, provided support.

The company plated automotive engine parts and other components, and had equipment for analyzing metal-ion concentrations and treating water. The analytical and manufacturing foundation Shigeta sought coincided with his father’s desire to develop a new business pillar, leading to the creation of a healthcare division in 2004. The beginning of cosmetics development, manufacturing and selling as a company business, and the birth of OSAJI were separate stages.

OSAJI launched as a brand in 2017 and opened its first directly operated store in Yanaka. Its name comes from “osaji,” a term associated with the image of blending medicines with a spoon. In October 2023, it was spun off from Nitto Denka Kogyo, and Shigeta became representative director of OSAJI Inc.

Expanding Its Fragrance Proposals through Collaboration with Taeko Kusaba

One point of contact that brought people to OSAJI was its collaboration with hair and makeup artist Taeko Kusaba. Shigeta had met Kusaba on a shoot for an earlier brand; Kusaba later became a regular user of OSAJI’s body gel and shared it with others. When a staff member showed Shigeta Kusaba’s post, an opportunity arose to work together again.

Developed with Kusaba, kokyu, meaning “breathing,” is a series that expanded from body gel into haircare. Collaborating through conversations about products someone genuinely wants also overlaps with Shigeta’s aim of developing products that respond to their users.

We place importance not on being “for sensitive skin,” but on being “usable even by people with sensitive skin.”
Masakazu Shigeta

Shigeta’s idea was to create room for people to enjoy skincare and makeup rather than dividing them solely by their skin concerns. Fragrance, too, would become an entry point for OSAJI’s thinking about daily life.

On October 2, 2020, the brand launched its first perfume, an eau de toilette. Initially, five flowers—violet, peony, narcissus, wisteria, and yellow daylily—served as subjects for nostalgic feelings and scenes. Wisteria was associated with the sound of rain against a misted window and the flowers swaying beyond it.

In 2021, kako, a place to blend scents for the home, opened in Kuramae. On March 26, 2025, the eaux de toilette were renewed as five fragrances named with prepositions, and three more were added on March 11, 2026. The current eau de toilette range comprises eight fragrances.

The Brand’s Approach

Connecting Fragrance with Time and Place through Prepositions

The names chosen for the 2025 renewal were at, of, in, for, and over. Prepositions frame time and space and create relationships between words. OSAJI linked that role to the way a fragrance added to clothing and makeup changes the atmosphere or mood of the day.

For example, over carries the phrase “over the memories” (“beyond memories”). It combines the impression of rush grass with neroli and slips roasted hojicha tea into the sweetness of oud. It also contains stem extract of shichito-i, a plant grown in Oita Prefecture. Familiar traces of plants and tea are layered with impressions of darkness and smoke to shape a fragrance connected to memory.

Meanwhile, in, associated with “in the sun,” combines lavender and cherry, adding the sweetness of musk and other notes to a cotton-like softness. Rather than simply classifying scents by plant names, the collection moves between the scenes suggested by words and the textures created by the compositions.

The fragrances on, by, and beside, added in 2026, continue the same naming approach. Beside, named “you beside me” (“by your side”), layers impressions of pear and green tea with Earl Grey and extract of rugosa rose flowers from Hokkaido. A phrase indicating a relationship with someone nearby creates a new scene for fragrance. Domestic plant ingredients contribute to depicting that scenery; this does not mean the whole collection is made exclusively from natural fragrance materials.

The Experience of Recreating a Home’s Fragrance at kako

Kako extended the idea of choosing fragrance into the experience of blending it. A 2022 interview describes a system in which customers select and combine scents from 12 essential-oil blends divided into four groups by evaporation rate. The products made are room fragrances and essential oils, whose uses differ from OSAJI’s eau de toilette for the skin.

What Shigeta imagined was a home’s fragrance that could be passed down like a family crest while also changing. Rather than fixing a scent once it has been chosen, he leaves room to blend it again according to age and mood. He hopes that the experience of making fragrance will also help people imagine what other creators were thinking when they encounter their work.

“Kotoba no Utsuwa”: Making Handwashing a Fragrance Experience

“Kotoba no Utsuwa,” or “Vessels of Words,” born of a collaboration with Madoki Yamasaki, is a hand soap rather than a perfume. It translates the tagging—the drawn lettering—of Yamasaki, whose creative practice spans music and words, into the relief of a white porcelain bottle.

Washing your hands is also one of the most immediate ways to enjoy fragrance.
Masakazu Shigeta

Shigeta placed vetiver at the center, adding cardamom and coriander for nuances suggestive of Asia, and sage and grapefruit for an airy lift. Vetiver (in Japanese) is a fragrance material obtained from the roots of a grass-family plant. The choice reveals an effort to create both weight and lightness within the brief act of handwashing, with the scent of roots as its axis.

The container was based on an antique komprador bottle Shigeta had acquired, of a type used to export soy sauce during the Edo period. It can become a flower vase once empty, and its appearance changes with the hands and time of the person using it. Seeing words, encountering fragrance, and washing hands: the collaboration was fashioned into an object through which each of these acts can be repeated in daily life.