Seasons as Cultural Timekeepers in Japan’s Traditional Calendar
Why Microseasons Still Shape Japanese Life Beyond the Modern Clock
When staying in Japan for an extended period, there is one insight that allows for a deeper understanding of the country than most visitors ever gain. Even in the hyper-modern landscape where traditional lifestyles seem forgotten, Japan’s culture continues to be quietly governed by the seasons. But why do “seasons” hold such elevated significance in Japanese culture? In this piece, we explore that question through the traditional lunisolar calendar that has been used for over a thousand years, focusing specifically on the “24 solar terms / 24 sekki (二十四節句)” and “Japan’s 72 microseasons (七十二候)”, and how they connect with agricultural life in premodern Japan.
The year was divided into 24 solar terms, and then into 72 microseasons, forming a remarkably nuanced calendar system. These divisions, known respectively as 24 solar terms and 72 microseasons, originate in ancient China. Each of the four seasons—spring, summer, autumn, and winter—was divided into six 24 solar terms markers with poetic names like 「立春 (Risshun, “Beginning of Spring”)」, 「春分 (Shunbun, “Spring Equinox”)」, and 「夏至 (Geshi, “Summer Solstice”)」. The 72 microseasons system subdivided each of these into three five-day segments, each with its own evocative name that described a minute change in the natural world. These microseasons were not just poetic flourishes—they were designed to be comprehensible and useful to everyday people, embedding seasonal wisdom directly into the structure of daily life.
To help readers unfamiliar with these terms, here are three spring-related 72 microseasons examples, along with their 2025 dates:
「東風解凍」—meaning “Spring winds thaw the ice,” reflecting the belief that 春 (spring), governed by the east in the Chinese Wuxing system (陰陽五行), arrives on the wind; this occurs from February 3 to 7.
「雀始巣」—“Sparrows begin to nest,” indicating the start of warmer spring weather; observed from March 20 to 24.
「桜始開」—“Cherry blossoms begin to bloom,” marks the arrival of peak springtime; dated from March 25 to 29.
With 72 such seasonal names, each about five days long, this calendar system offers a deeply textured awareness of natural phenomena. The vocabulary is poetic yet functional—easy for farmers to grasp and incorporate into their lives.
Although the 24 solar terms and 72 microseasons were inherited from China, they were long accepted in Japan as-is. However, by the Edo period, accumulated local knowledge led to adjustments aligning the calendar with Japan’s distinct climate. Both the 24 solar terms and 72 microseasons were inscribed into the lunisolar calendar (太陰太陽暦) used prior to Japan’s adoption of the Western Gregorian calendar in the Meiji era. Even today, terms like “Risshun has passed (立春が過ぎた)” or “Today is Shunbun (今日は春分だ)” still appear in conversation and media, a testament to their continued cultural relevance.
The 24 solar terms system has deep roots in ancient China’s Yellow River agricultural zones. For agrarian societies, predicting and reading seasonal changes was vital to securing food. To address the discrepancies of the lunar calendar, the lunisolar calendar was developed, incorporating solar markers tied to celestial events and seasonal phenomena. These terms were chosen with clarity and simplicity in mind, intended to be accessible not just to scholars but to ordinary farmers.
Japan’s oldest historical record, Nihon Shoki (720 AD), states that Chinese calendrical knowledge was introduced via the Korean peninsula around the 6th century, and the 24 solar terms was soon incorporated into Japanese life. But because Japan’s climate differs significantly from China’s, many of the terms didn’t align well with local experience. This mismatch prompted the gradual development of Japan’s own seasonal framework, leading to the creation of supplemental indicators known as 「雑節 (zassetsu)」, including 「節分 (Setsubun)」, 「彼岸 (Higan)」, 「八十八夜 (Hachijūhachiya)」, 「入梅 (Nyūbai)」, and 「二百十日 (Nihyakutōka)」. These additions remain vital components of seasonal festivals even today.
In the Edo period, astronomer Shibukawa Harumi undertook a radical calendrical reform, adjusting the 72 microseasons to better reflect Japanese realities. His Jōkyō calendar (貞享暦), officially adopted in 1685, replaced many Chinese seasonal names with Japanese references. For instance, the Chinese term 「玄鳥至 (“Swallows arrive”)」 was replaced by 「雀始巣 (“Sparrows begin to nest”)」, and 「雷乃発声 (“Thunder begins to sound”)」 was supplemented by 「桜始開 (“Cherry blossoms begin to bloom”)」, because sparrows and cherry blossoms were more immediately recognizable and meaningful to Japanese people. This adaptation shows how Japan absorbed Chinese knowledge while reshaping it into a uniquely local worldview.
The relevance of 24 solar terms extended beyond naming—it structured the agricultural calendar and guided community life. Farming societies depended on accurate timing to sow, transplant, and harvest crops. For example, 「八十八夜 (Hachijūhachiya)」, the 88th night after 「立春 (Risshun)」, was considered the safest time to sow seeds, signaling the end of frost. In 2025, this falls on May 1. 「穀雨 (Kokuu, “Grain rains”)」, the final spring solar terms, referred to nourishing spring rains that benefited crop sowing.
「芒種 (Bōshu)」, early summer’s seed-planting season, marked the ideal time for rice transplantation. Spring and autumn equinoxes also marked key ritual moments, aligning with “彼岸 (Higan)”, the Buddhist ancestral remembrance period. These calendar markers offered not just meteorological guidance but a rhythmic backbone to community rituals and festivals.
For many Western readers, the lunisolar calendar and its continual adjustments might seem perplexing. The old lunar calendar, based on the moon’s phases, naturally drifted about 11 days per year, creating a disconnect with solar seasons. The 24 solar terms acted as solar “anchors” to correct this drift. For centuries, these seasonal terms gave farmers and officials a reliable framework for synchronizing planting schedules and ceremonial observances.
What’s striking is how Japan evolved this system from its Chinese roots through centuries of adaptation, driven by necessity, cultural imagination, and scholarly effort. In fact, during the Edo period, the Tokugawa shogunate saw accurate calendars not just as practical tools but as political stabilizers. Calendar reform helped prevent crop failures and social unrest, showing how deeply entwined cosmology and governance could be.
Even today, many Japanese people unconsciously adhere to these seasonal rhythms. Visitors often note how Japanese lifestyles still shift subtly with the seasons—whether it’s food, festivals, or clothing. That’s the legacy of a system developed over a millennium, embedded into the nation’s collective sensibility.