Think About Interiors Day (Interior wo Kangaeru Hi)

What is Think About Interiors Day?

Every year on April 10th, Japan observes "Think About Interiors Day," established by the Nippon Interior Fabrics Association (NIF). April is the season when new chapters in life begin — school entrance, new jobs, relocations — making it an ideal time to reconsider your living space and work environment. The date itself also comes from a wordplay: "10" ("jū") can be read the same as the word for "living" (住, "jū"). This day is about more than just decorating a room — it's about designing the foundation for a richer, more fulfilling life that's truly your own.

Scientific Facts About Living Spaces and Wellbeing

Interior design isn't just about appearances — it's deeply connected to mental recovery and mental health.

• The effect of "biophilic design": Incorporating natural elements like houseplants into a space has been scientifically shown to lower levels of the stress hormone cortisol. Some studies even suggest that simply having greenery in a room can boost concentration by 15% — proof that how a space is designed can shape brain performance.
• The psychological impact of color: The colors of your wallpaper or curtains directly affect your emotions. Blue tones, for example, can lower your heart rate and promote relaxation, while yellow tones can boost dopamine release and encourage communication. Choosing interior colors is essentially writing an "environmental prescription" for your own emotions.

Facts About Spatial Design and Behavioral Economics

The simple act of rearranging furniture can change family conversations and your own habits.

• Using "nudges": Placing a book you want to read next to your favorite chair, or leaving exercise equipment out where you'll see it — small changes in interior arrangement can make it much easier to build new habits without relying on willpower. In this sense, your interior is a blueprint for designing your "ideal self."
• Lighting and your body clock: Exposure to strong blue light in the evening suppresses melatonin, the hormone that promotes sleep. Switching your interior lighting to warm, indirect light after dusk helps regulate your internal clock and scientifically supports a more comfortable wake-up the next morning.

Fascinating Facts About Interiors

• The hidden role of curtains: Beyond blocking light and protecting privacy, about 70% of a room's heat is lost or gained through its windows. Choosing curtains of the right thickness and material for the season is a scientifically grounded way to improve energy efficiency, protecting both your wallet and the environment.
• The 70:25:5 golden ratio: There's a golden ratio for making a room look beautiful — allocating 70% to a base color, 25% to a main color, and 5% to an accent color lets even beginners create a well-balanced, professional-looking space.
• Why Scandinavian interiors developed the way they did: Nordic countries developed such a strong sense of design partly because long winters mean more time spent indoors. The concept of "hygge" (cozy, comfortable time) is essentially wisdom born from harsh natural conditions — using interior design to maximize emotional wellbeing.
• Clutter and brain capacity: When your field of view is full of objects, your brain constantly processes that visual information, draining cognitive resources. Decluttering your space and creating "empty space" frees up your brain's working memory, boosting decision-making and creativity.
• Scent as interior design: It's not just about what you see — "scent design" through aromas and diffusers matters too. Because smell is directly linked to the limbic system, which governs emotion, establishing a signature scent in your space can act as an instant switch into relaxation mode.

Tips for Spending Think About Interiors Day

• On April 10th (Think About Interiors Day), pick just one spot in your home where you spend the most time, and tweak the view from that spot. Adding a favorite photo or a small flower can dramatically change how fulfilled you feel
• Reconsider your lighting. Try turning off the main ceiling light for a few hours in the evening and relying only on a desk lamp or floor lamp. The depth created by shadows and gentle light can gently ease the tension built up from a new fiscal year
• Start with decluttering. Let go of one item you don't need, and imagine what you'd like to place in that newly empty space (or leave it empty). Thinking about your interior becomes a luxurious moment of reflection on what truly matters to you right now
• Reconnect with the colors and materials (wood, fabric, stone, etc.) you genuinely love. Rather than chasing trends on social media, trust your own instincts about what feels comfortable to touch and calming to look at, and plan to refresh a small cushion cover or rug

When You Soften the Corners of a Square Room with Kindness, Your Home Becomes a "Charger for Life"

April 10th is a day to give thanks to your "home" — the partner that sends you off each morning and welcomes you back each evening — and to deepen that relationship. Changing your interior is, in essence, expressing your inner self to the outside world. You don't need to aim for a perfect showroom. All you need is a place where you can be yourself and take a deep breath. Building such a space, little by little, gives you a sense of security: no matter how strong the wind blows outside, you can always return to yourself once you're home. Let in the fresh breeze of the new fiscal year, and design a "magical space" that brings more color and calm to your everyday life.