Autumnal Equinox Day (Shubun no Hi)

What Is Autumnal Equinox Day?

Around September 23rd each year — the date determined by the precise astronomical moment the sun crosses the autumnal equinox point — Japan observes the national holiday "Autumnal Equinox Day." Established in 1948 as a successor to the former imperial ritual "Shuki Korei-sai," it is designated as a day "to honor one's ancestors and remember those who have passed away." Marking the point when the sun rises due east and sets due west, with day and night nearly equal in length, this is the moment when the heat of summer gives way to the crispness of autumn.

The Astronomical and Cultural Significance of Balanced Day and Night

The equinox has long served as an important marker in agriculture and religious tradition, a moment when people sensed the order of the cosmos.

• The concept of Higan: Around this time, when the sun sets due west, Buddhist tradition holds that the boundary between the Western Paradise (the Pure Land, or higan) and this world (shigan) becomes especially thin. The Japanese tradition of honoring ancestors during this period reflects an elegant connection between the sun's astronomical path and the spiritual world.
• The midpoint of the year's cycle: The cycle that began with the spring equinox now turns toward harvest and gratitude. Historically, ancient civilizations around the world used these "equal day" points as anchors for their calendars, scheduling agricultural work and rituals around them.

Circadian Rhythms and the Brain

As daylight hours shorten, our bodies naturally shift from a mode of "activity" toward one of "reflection and consolidation."

• From serotonin to melatonin: As daylight decreases after the autumnal equinox, the brain's production of serotonin (which supports activity) decreases, while the timing of melatonin (which governs sleep) shifts. Being mindful of this — for example, by getting morning sunlight — can help prevent seasonal mood changes common in autumn.
• A time for introspection: Longer nights mean the brain has more capacity to turn inward, processing memories and engaging in self-reflection. Deep thinking during this period can strengthen the prefrontal cortex and support long-term planning.

Things Worth Knowing About the Autumnal Equinox

• The precise truth about "equal day and night": In reality, due to atmospheric refraction, daytime on the equinox is actually a few minutes longer than nighttime. Understanding this small gap between the "defined" equinox and the physical reality of daylight is a good exercise in scientific literacy.
• A modern "wellbeing check-in": Increasingly, people treat the autumnal equinox as a moment to take stock of their physical and mental wellbeing — reviewing progress from the first half of the year and thinking about how to allocate energy heading into winter.
• The nutrition of ohagi: Ohagi, sweet rice cakes named after the bush clover (hagi) that blooms in autumn, are traditionally eaten around this time. The saponins and fiber in the red bean paste are thought to help soothe digestive systems tired from summer.
• Color psychology and "autumn colors": The reds and oranges associated with autumn leaves tend to activate the parasympathetic nervous system, promoting a sense of calm. Incorporating autumn tones into your home or wardrobe can help guide the brain into a more relaxed state.
• The "harvest" as a measure of progress: Just as autumn brings the harvest of seeds planted earlier, the equinox is a natural checkpoint for objectively reviewing how much your efforts and investments throughout the year have paid off.

Tips for Enjoying Autumnal Equinox Day

• Take stock of your "harvest" from the past six months — listing your accomplishments and the lessons you've learned can boost your sense of confidence heading into the second half of the year.
• Visit family graves or talk about ancestors to reconnect with your own roots. Recognizing your place within a long chain of history can offer a broader perspective and ease everyday worries.
• Update your daily rhythm for autumn — dim the lights a little earlier and make time for reading or meditation. Adjusting your light exposure is one of the simplest and most effective forms of self-care.
• Savor seasonal foods with all five senses, paying attention not just to taste but also aroma and texture — a way to anchor an overloaded mind in the present moment and build emotional resilience.

Let the Golden Balance of Light and Shadow Bring You Quiet Harmony

September 23rd is a day to pause and celebrate your own "inner harvest." As day and night reach perfect balance, take this moment to reset from the busyness of recent months and rediscover your own sense of equilibrium. The autumnal equinox reminds us of a basic truth of nature: every effort has its proper season of harvest. After months of pushing forward since the new fiscal year began, take a moment to slow down and savor what you've gained so far. The plans you make with a settled mind today can carry you through the new season with wisdom and steady confidence. Let's welcome a wonderful autumn together, at a gentle pace.