Rough Co., Ltd. Surpasses 150 Enrollees in Six Months for 'Flavor Koji Specialist® Certification Course,' Meeting Demand for 'Adult Hobby Engagement' Among Women in Their 50s

Rough Co., Ltd. (Headquarters: Minato-ku, Tokyo; CEO: Shiseki Nagabuchi, hereinafter 'Rough') has launched an experiential online course titled 'Flavor Koji Specialist® Certification Course' targeting adults, particularly those in their 50s. The course, launched on December 26, 2025, enables participants to deeply understand fermentation and cultivate koji with their own hands, mastering lifelong fermentation techniques from home. Within six months of launch, enrollment has surpassed 150 students.

Rough operates under the brand purpose of 'Designing fulfillment through learning and hobbies,' offering experiential online courses in art, calligraphy, cooking, crafts, and sweets—fields that inspire passion among adults.

The company promotes 'Learning Leisure' (Manabirurejā), a new lifestyle consumption trend where individuals invest time and money in learning and hobbies to enrich their lives, much like travel or dining out.

This course goes beyond memorizing recipes. Participants learn the essence of fermentation and develop the ability to cultivate koji tailored to seasonal ingredients, family preferences, and desired fermented products. Centered on koji-making, the course aims to equip learners with lifelong fermentation skills applicable to creating salt koji, soy sauce koji, sweet koji, miso, and other fermented foods for everyday use.

More than just recipes: Learning the essence of fermentation.

1. Background and Objectives of the Course

In the era of 100-year lifespans, how individuals in their 50s and beyond spend their time and whether they have passions significantly impact life satisfaction and sense of purpose.

For adult women who have shouldered roles in parenting, work, household management, and caregiving, hobbies and learning are not mere pastimes.

They are: Time to rediscover one's sensibility, Experiences to encounter a new self, Opportunities to build human connections.

However, traditional online courses face several challenges:

・End after passively watching videos ・Difficulty sourcing required tools independently ・High dropout rates due to solitary learning ・Limited connection with instructors or peers

To address these issues, Rough has developed an 'At-Home Atelier Model'—a course design integrating online lessons, material kits, instructor support, and community experiences.

From the moment it arrives, your home becomes an atelier. Create, connect, and become passionate.

That is the essence of Rough’s experiential online courses.

The 'Flavor Koji Specialist® Certification Course' encourages participants to engage all five senses—aroma, touch, color, and temperature—when working with koji. Learners cultivate koji based on personal and family preferences and intended fermented products, gaining the ability to enhance daily meals.

Rather than merely acquiring cooking recipes, participants learn the fundamentals of fermentation to draw out sweetness, umami, and aroma tailored to their needs. The course also provides simple, delicious, and sustainable recipes to seamlessly incorporate koji seasonings like salt koji, soy sauce koji, and sweet koji into daily meals.

Sensing the changes in aroma, texture, and flavor as koji develops—this hands-on time cultivating fermented foods makes daily meals more enjoyable and fulfilling.

Beyond the joy of crafting additive-free seasonings, the course offers practical recipes that make it easy to use finished koji products in everyday cooking. The joy of creation extends to the smiles of family members enjoying the food, making this one of the course’s key appeals.

The deeper one understands fermentation, the more enjoyable daily cooking becomes.

Through learning, the course aims to spread the joy and solid techniques of homemade fermentation into everyday life, preserving and passing on Japan’s traditional fermentation culture to future generations.

2. What is the Flavor Koji Specialist® Certification Course?

An experiential online course that teaches the essence of fermentation and enables authentic traditional fermented food production at home.

This course emphasizes more than technical skills:

The joy of selecting koji to bring smiles to oneself and family,

The richness of enjoying handmade time through sensory engagement with koji,

The fulfillment of incorporating additive-free fermented foods into daily life.

What You Will Learn:

・Fundamental fermentation principles applicable to various fermented foods

・How to assess koji condition through aroma, touch, color, and temperature

・Ability to create original koji-based dishes without relying on recipes

・The pleasure of crafting premium, additive-free seasonings at home

・Potential pathways to commercialization or teaching, if desired

Recommended For:

・Those who wish to support their family’s health through meals ・Individuals in their 50s seeking a new hobby ・Those wanting to enjoy serious home-based learning ・People looking to connect with like-minded peers ・Anyone seeking a passion for the latter half of life

Time spent engaging with koji enriches daily life.

3. Features of Rough’s Experiential Online Courses

Feature 1: Course Kit Delivered to Your Home

To ensure beginners can start without confusion, Rough delivers all necessary materials and tools in a curated kit.

'I don’t know what to buy' 'I don’t want to make mistakes choosing tools' 'I want to start immediately upon delivery'

These concerns are minimized through thoughtful design, enabling learners to take their first step with confidence.

Kit includes instructor-selected items.

Feature 2: Learn at Your Own Pace via Video

As an online course, participants can learn from home at their own pace.

Unclear sections can be reviewed multiple times, making it accessible even for busy individuals.

Feature 3: Instructor Support

Rough’s courses are not one-way video lectures.

Through instructor feedback, corrections, and Q&A support, even beginners can confidently create their works.

Feature 4: Connect with Peers

Connecting with fellow learners enhances motivation and enjoyment.

Sharing creations, exchanging inspiration, and encouraging one another transforms hobbies from solitary time into a community experience that enriches life.

Feature 5: Course Design That Captivates Adults

Rough prioritizes more than skill acquisition.

The course is designed to naturally inspire positive motivations such as: 'I want to try this' 'I want to complete my work' 'I want to show it to someone' 'I want to improve further'

4. Comment from Shiseki Nagabuchi, CEO of Rough Co., Ltd.

'We are delighted that the 'Flavor Koji Specialist® Certification Course' has surpassed 150 total enrollees.

We believe the reason so many have joined is their resonance with our approach—not just learning fermented food recipes, but understanding fermentation mechanisms and gaining the ability to apply knowledge independently.

At Rough, we emphasize integrated learning across all courses: combining video instruction with material kits and instructor support. For this course, we believe the ability to practice at home has contributed to sustained engagement.

Fermented food creation is not only about enjoying the final product, but also about mindfully observing changes in aroma, touch, color, and temperature as it develops,