“A band of samurai snuck into the castle at 11:00 PM” — something feels off, doesn’t it? While it may sound exciting, in Edo-period Japan, no one would have understood the concept of “eleven PM.” Time was measured differently back then: the infiltration might have taken place, for example, at the beginning of the Hour of the Rat. Have you ever wondered how time was actually measured in samurai-era Japan? When a day was divided into twelve “hours,” each of varying length—changing with the seasons, according to one of the twenty-four sekki.
In the world of the Tokugawa, time was not a line but a garden of moving circles, where everything remained in a silent dance of light and shadow. The kanji 時 combines the sun (日) and a temple (寺), reminding us that this was not time that one “had,” but time that one “experienced” together with nature. At noon, a summer hour could last nearly 150 modern minutes, while in winter it might be barely 45. This irregular system, futei-ji (不定時), was not a primitive relic but a subtle instrument harmonized with the rhythm of nature; it allowed each moment to have its own unique flavor.
An elaborate sound-based infrastructure ensured the accurate tracking of futei-ji in Edo. In residential districts, taiko drums thundered; in public squares, great kane bells rang; and in ports, mortar cannons saluted the hour. A watchman with a gnomon measured the shadow, adjusted a tablet, and signaled the bell tower—thus forming an audible web of time that wrapped around the city. Overseeing it all was the Astronomical Bureau, which every few weeks issued new tables of koku (hour) lengths. On a lighter note, folklore offered even simpler methods: ninja would “measure” the moment by the width of a cat’s pupils, and if no furry chronometer was at hand, one only had to… check which nostril was easier to breathe through.
In townspeople’s homes, senkō-dokei—spiral incense clocks—burned slowly, marking out half a koku, perfect for cooking rice; in samurai residences, lacquered water clocks dripped steadily, and a drifting cypress leaf on the water’s surface indicated the passing moment. In the pleasure quarter of Yoshiwara, each incense stick was a currency of love (15 minutes): as the smoke faded, kamuro attendants lit the next one, charging more strictly than any tax collector. Edo’s clocks didn’t just measure time—they told stories of it, they smelled, resonated, and shimmered. Let’s see how, in Edo, time was less mathematics and more poetry.
In the Edo period, time was not equal. It did not flow like today’s hours, counted with the indifferent precision of quartz watches, but rather breathed with the rhythm of nature. In the Japan ruled by Tokugawa shoguns, the day was not divided into twenty-four equal units but into twelve variable segments—six for day, six for night. This system was called futei-ji (不定時), meaning literally “non-fixed time”—and indeed, each of these “hours” varied in length depending on the season. In summer, daytime hours lengthened, while nighttime hours shortened; in winter, the opposite occurred—the day shrank to a minimum, and night spread across most of the day.
In practice, this meant that “9:00 AM” in May and “9:00 AM” in December lasted completely different amounts of time—though no one in Edo thought of time in terms of Western minutes. The traditional Japanese “hour” was not a fixed unit, but a flexible interval—more like a stage of the day than a mathematical quantum. And since day and night were always divided into six parts, their lengths shifted smoothly with the solar day’s changes. These shifts occurred twenty-four times a year, in accordance with the points of the lunisolar calendar—such as shunbun (spring equinox), taisho (great heat), or kanro (cold dew) (more about the calendar and 72 seasonal phases can be found here: The 72 Japanese Seasons, Part 1 – Spring and Summer in the Calendar of Subtle Mindfulness and here: 72 Japanese Micro-Seasons, Part 2 – Autumn and Winter in the Calendar of Conscious Living). Only during the equinoxes did day and night—and thus daytime and nighttime hours—become equal.
In everyday life, people did not perceive time as a precise numerical system but as something sensory and cyclical. Time was felt through the warmth of the sun on the skin, through the sound of bells ringing at dawn and dusk, through the fading of stars or the appearance of shadows on a garden path. At sunrise—the “Hour of the Rabbit”—peasants awoke, folding their tatami mats. At the “Hour of the Horse,” around noon, they rested from labor. And when the “Hour of the Rooster” came—dusk—paper lanterns were lit, and preparations for the night began.
The futei-ji system might seem illogical today, but in a world that knew neither electricity nor GPS nor digital calendars, it was, in fact, practical. It adapted to the natural rhythm of light and dark, allowing people to live in harmony with nature’s cycles. It was not time that one “possessed,” but time that one lived through.
Before we delve into the ingenious marvels of the Edo period, it is worth pausing for a moment to consider the language itself. Because the way the Japanese spoke—and still speak—about time reveals a completely different, culturally embedded concept of its nature. In contrast to the Western Greco-Latin heritage, where time is chronos—an abstract axis of identical units—the Japanese language is imbued with an intuition of cyclicality, transience, and the rhythm of life.
The most fundamental character for time is 時 (toki or ji), used for example in the word tokei (時計 – “clock,” literally “time measuring device”). The character 時 consists of two parts: on the left, the radical 日 – “sun” or “day,” and on the right, 寺 – “temple.” The second component is no coincidence: it was in Buddhist temples that time was traditionally measured, with bells rung at set intervals. In other words, the very writing of the word “time” points to its connection with the sun’s cycle and the spiritual space of the temple.
Another important character is 刻 (koku, kizamu), meaning “to carve,” “to engrave,” and in the context of time – “to measure.” Time in Japan did not “flow,” but was “carved” into reality—in wood, in bronze, in the sound of a drum, in lines etched onto a clock face. In the Edo period, the term koku also referred to one of the twelve “hours” of the day, which were literally called “carvings” or “cuttings” of time.
The term futei-ji (不定時), describing the variable time system in effect until the end of the Edo period, is also fascinating. It is composed of three characters: 不 (“not” or “non-”), 定 (“fixed,” “established”), and 時 (“time”). Together, they mean “non-fixed time,” “variable time”—which perfectly expresses the philosophy behind the system. In contrast, the later-introduced Western time system was called jōtei-ji (定時) – “fixed, regular time,” the kind we use to measure days today.
It is also worth mentioning the old way of referring to times of day. Instead of saying “three PM,” one might say uma no koku (午の刻) – “the time of the Horse.” The twelve hours of the day corresponded to the twelve signs of the Chinese zodiac (十二支 – jūnishi), which served as hour names. These terms were so deeply rooted that traces of the old system still remain in modern Japanese: for example, the words gozen (午前 – “before noon”) and gogo (午後 – “afternoon”) both contain the character 午, meaning “horse,” which in the traditional system marked noon.
Time in the Japanese language was not something external, but rather something present in rituals, seasons, names, in the structure of the calendar, and even in the syntax of thought itself. It was not digital time but imagistic time—described through metaphors of light, the zodiac, incense, and the sound of bells. And that is precisely why this system, though it may appear chaotic to the modern eye, was so deeply coherent with the culture of premodern Japan.
From the dawn of Japanese statehood, time was measured in relation to sunrise and sunset. However, the precise twelve-division scheme of variable hours began to spread in the 7th century alongside the lunisolar calendar. Under the rule of the Tokugawa shoguns, the system rose to become a pillar of daily life. It was called futei-ji – “non-fixed time” – and was regarded as a natural expression of harmony with the world, as innate as the solar and lunar cycles it helped to organize.
Futei-ji divided the day into twelve segments, six for daylight and six for night. Each of these was called koku (刻) or simply toki (時), but they had no fixed length—they expanded with the dawns of summer and contracted in the darkness of winter. From an astronomical standpoint, the system was elegantly simple: the first daytime koku began precisely at daybreak, the last ended with sunset; then the nighttime koku began, continuing until the next dawn. Six evenly divided portions of light and six of darkness—nothing more was needed by a farmer, merchant, or monk to synchronize fieldwork, gate-side trade, or the recitation of sutras.
To our modern sense of time, such an arrangement may seem troublesome, but for an agrarian society it offered only benefits. Rice ripened in the rhythm of the sun, not of the clock; the prayers of Buddhist monks echoed at dawn and dusk, so their liturgical calendar, too, had to be flexible. From the Tokugawa perspective, variable hours also served a political function: they effectively distinguished Japan from the “barbarian” West and fit into the broader ideology of sakoku—the closing of the islands to foreign dominance.
The key to the functioning of futei-ji was a precise chart of hour lengths prepared by court astronomers (天文方 tenmonkata). Together with poets and mathematicians, they produced calendars in which the year was divided into 24 sekki—solar “nodes” marking, for example, minor cold (shōkan), great heat (taisho), or white dew (hakuro). At each of these points, the lengths of daytime and nighttime koku were corrected by a few moments (what we would now call “minutes”): hence the frequent phrase in historical sources that “time was adjusted twenty-four times a year.” From at least the 17th century, announcements with detailed tables were distributed to all major temples and castles, from which the news spread further via the beating of drums and ringing of bells.
With the arrival of European clocks, Japanese craftsmen—such as Yasui Santetsu, author of the Jōkyō calendar reform of 1684—faced a conundrum: how to make metal and springs comply with non-uniform time. They solved it by inventing wadokei with dual day–night balances, adjustable dials, and zodiac signs rotating across them. The mechanism ticked at a steady pace, but the hands passed over indexes manually shifted every few days—so that their path was shortened or lengthened according to the season. Thus were created clocks that could “breathe” with the sun.
In Edo, the accurate measurement of futei-ji relied on an elaborate infrastructure of auditory signals. In residential districts, drums (taiko) echoed; in large squares, bells (kane) rang; and in ports, small mortar cannons fired. A watchman on duty measured the shadow on a portable gnomon or checked a water clock’s readings; if the table indicated a change in koku length, he marked it in chalk on a tablet and relayed the information to the bell tower. In this way, a kind of audible time grid was created, binding the city together before the first gas lamps had ever flickered to life.
As a result, futei-ji was not a primitive relic from before mechanization, but a subtle instrument synchronized with the rhythm of nature and the needs of society. Its irregularity allowed people to think of time not as a geometric abstraction but as something living; it made each part of the day possess its own taste, scent, and color—from the cool blue of the “Hour of the Tiger” to the glimmering gold of the “Hour of the Rooster.” Only the modernizing cut of the Meiji era transformed these pulsing koku into the 24 steel segments that now define our journey through the day.
Hours of Day in Edo
Before Tokugawa Ieyasu took power and closed Japan off from the world, time had already crossed its borders in the form of ticking European clocks. In the 16th century, Portuguese missionaries and Dutch merchants—travelers from the far West—brought with them metallic wonders: lantern clocks with verge escapements, whose hands moved with a regularity foreign to Japanese daily life. To the island’s inhabitants, these clocks were both fascinating and... useless. They measured twenty-four equal hours—rigid, unyielding, and indifferent to the length of day and night. In other words, entirely mismatched with the futei-ji system, which lived in the rhythm of changing light. How could an hour last the same in summer and winter—when summer days are clearly longer than nights—so how could every hour possibly be the same?
But Japanese artisans were not the sort to reject what they didn’t understand—they transformed it. As early as the 17th century, the first wave of native clocks emerged—wadokei—designed specifically for variable time. Western solutions were not copied directly but were reimagined with the finesse of master swordsmiths or ningyō puppet-makers (more on that here: Karakuri Ningyō of Ancient Japan – Wooden Mechanical Robots That Served Tea, Danced, and Wrote). Western mechanisms became only a starting point—a base to be adapted to the Japanese spirit and practice.
How to cope with the fact that hours are longer in summer and shorter in winter? This is where the true magic of technique and aesthetics begins.
Some Edo clocks had movable dials on which zodiac symbols and their corresponding numbers were shifted manually. Others featured dual mechanisms—one for day, one for night—that could be switched at dusk. Still others regulated the foliot—a horizontal bar with sliding weights—by shifting the weights daily or every few days to speed up or slow down the clock’s operation.
A separate category was the pillar clocks (柱時計, hashira-dokei)—vertical constructions where a weight descended along a guide rail, measuring “hours” according to the season. Their scales were interchangeable: one for spring, another for winter. These clocks resembled bronze-carved calendars more than our modern timepieces. Their mechanisms were sophisticated, but their appearance—with ornamental engravings, family crests, and ebony-gloss wood—made them works of functional art that adorned palaces and the grand halls of castles.
The most magnificent among them are today known as “daimyō clocks” — costly, complex, and extraordinarily precise machines created exclusively on commission for the elite. Their value was immense — equivalent to twenty years of labor for an ordinary craftsman. They were not only symbols of status but also tools of responsibility: if the clock ran late, the entire retinue was delayed. In an age where punctuality was a ritual obligation, there was no room for error. Responsibility for its proper function was entrusted to one chosen individual — the guardian of time, who performed subtle calibrations every day at dawn and dusk.
The art of Japanese horology reached its peak just before the end of the Edo period. In 1851, Tanaka Hisashige — a technical genius and future founder of the company that would eventually become Toshiba — unveiled his masterpiece: the “Ten Thousand Year Clock” (万年自鳴鐘, Mannen Jimeishō). This clock was a microcosm: six dials that simultaneously displayed Japanese and Western time, moon phases, seasons, the lunar calendar, and solar terms. At its center, a rotating globe turned in sync with celestial movements. What’s more, the clock adjusted the length of the hours automatically to match the seasons — without the need for manual adjustment.
Today, this marvel of engineering can be admired at the National Museum of Nature and Science in Tokyo. Gazing upon it, one can perhaps feel what Tanaka himself once did — that time is not a line, but a garden of moving circles, where everything remains in a constant, silent dance. In the Edo period, clocks did not merely measure time — they told its stories.
The dawn over Edo was not awakened by a digital buzzer, but by the cawing of crows, the persistent cries of botefuri (more on them here: Wandering Street Vendors, the Botefuri – The Poor Entrepreneurs of Edo Who Carried the Metropolises of the Shogunate on Their Shoulders), and the deep tone of a bell striking six times — the signal that the Hour of the Rabbit (卯の刻, u no koku) had begun. At that moment, a farmer from Musashi province rolled up his tatami and took up his hoe, a merchant in Nihonbashi lifted heavy shutters, and a young samurai fastened his wakizashi to make it in time for the morning report at the shōgun’s castle.
Why did the bell strike six times during the Hour of the Rabbit? In the world of old Japan, the clock was not an instrument of precision but a poetic echo of the rhythm of day and night. The bell’s sound did not signify time through numbers, but through symbolism and convention, whose logic was deeply rooted in Buddhist cosmology and Confucian order. Though the day was divided into twelve hours corresponding to the signs of the Chinese zodiac, in practice each hour was indicated by a number of bell strikes — from nine to four. This meant that when the bell struck six times at dawn, it did not announce “six AM,” but the Hour of the Rabbit — the time when the sun cut through the mist over the fields and shopkeepers began to lift their shutters.
This seemingly mysterious system had its own order. The number nine marked noon and midnight, when the sun was highest in the sky or when light was farthest away — the perfect center of day and night. From that point, the number of strikes decreased — eight, seven, down to four, assigned to the hours furthest from the zenith: daybreak and the darkest part of the night. Interestingly, the numbers one, two, and three did not appear in this system at all. There were several reasons for this. First, low odd numbers — especially “one” and “three” — carried connotations of impurity, emptiness, or bad omens in both Buddhist and folk traditions. Second, one or two bell strokes were too easily lost in the city’s bustle, easily confused with other signals, and thus abandoned in favor of clearer and more resonant sounds. And third — perhaps most importantly — in Japanese tradition, time was meant to be felt, not counted. Six bell strikes did not need to indicate an exact hour but rather evoke a familiar time of day, known from the bamboo’s shadow, the scent of rice soup, or the sound of sandals on stone.
When the bell struck six times at dusk — the Hour of the Rooster (酉の刻, tori no koku) — lanterns on bamboo poles lit up the narrow alleys. Three koku later, at the Hour of the Boar (亥の刻, i no koku), the city fell into silence: guards took their places at the gates, and only the night courtesans waited for clients by the glow of paper lamps.
Edo was wrapped in a network of over 350 bell towers. Their rhythm formed an audible map of the city: nine strikes marked midnight and noon, six indicated dawn and dusk, while eight, seven, five, and four filled in the space between — then the cycle began anew. To this day in Kawagoe, the Toki no Kane (時の鐘) still rings out, its metallic voice echoing off the tiled roofs of lacquer and sweet shops.
In Zen monasteries, time was marked by taiko drums; in the mountain paths of Kii, echoes of the final strike carried through the sugi forests long after the sound itself had faded. In the ports, the fire brigade lit small mortars, and their thunder pierced the mist before reaching the fishermen’s boats on Edo Bay.
In townspeople’s homes, incense clocks (線香時計, senkō-dokei) burned quietly. One spiral of sandalwood took roughly half a koku to burn through — perfect for cooking rice or reducing soy sauce. Scholars used measuring candles with horizontal notches: as the flame reached the next groove, small metal balls would fall onto a tray, marking the next “tick” of the night. In the parlors of samurai households steeped in Confucianism, droplets from water clocks fell steadily, and a drifting cypress leaf on the surface signaled the passage of a koku.
In the illuminated pleasure quarter of Yoshiwara (more here: Born in hell, buried in Jōkanji – what have we done to the thousands of Yoshiwara women?), time was measured by aroma: one stick of sandalwood incense equaled a quarter-hour of delight. Kamuro — young attendants — discreetly placed the next stick, and customers paid in silver ryō for however much had burned. Here, time was fragrant, soft, and expensive — and the bill for incense was often more merciless than the toughest tax official.
Thus Pulsed Time in the Japan of the Tokugawa Shoguns
Not in equal, soulless minutes, but in the warmth of sunlight and the scent of sandalwood, in the ring of bells and the rustle of silk. The clock was reality itself, and each hour — of the Tiger, Horse, or Rooster — had a color and a taste no numbered dial could ever convey.
In the Edo period, time was on one hand a matter of utmost seriousness — bells rang, incense burned, dials shifted — and on the other… it often felt more like a gentle suggestion than a strict unit. Especially when one peeks into the borderlands of folklore, legend, and everyday superstition. While the samurai measured time by the shadow of a fan, and monks listened to the sound of a temple drum, the cat — oh, the cat knew best what time it was.
The Japanese of old truly believed that a cat’s pupils could serve as a… clock. At dawn and dusk — wide as lanterns, at noon — narrow as needles (as mentioned here: Ninja in Retirement - What Happened to Shinobi During the Peaceful Edo Period?). Some even claimed that if you had no clock and wanted to know the time, all you needed was to grab a cat and look deep into its eyes. The only question is what the cat might think of that — cats are not particularly known for altruism. In Kagoshima, there still exists a temple dedicated to the seven cats of Shimazu Yoshihiro — the brave daimyō who, according to legend, watched their eyes to know when to rest during battles. Some historians laugh, others remain respectfully silent.
And when it comes to extraordinary senses of timing — ninja time deserves its own calendar. According to Shōninki, an old Japanese manual of espionage, the ideal hours for moving in the shadows were… Boar, Rat, and Tiger. In other words: late evening, deep night, and early dawn — precisely when the average guard snores and the moon trembles in a bowl of water. Everything was subordinate to strategy: during the Hour of the Rat, you slip through a fence; at Tiger, you don a monk’s disguise; and at Boar, you prepare your escape (more shinobi techniques here: Encoding the Wind – Secret Communication Techniques of Ninja Schools During the Sengoku Wars).
But that’s not the end of surprising philosophical truths — for old country diviners believed you could tell whether the hour was even or odd… simply by breathing through one nostril. Yes, just plug one side and feel which one “draws” better…
No wonder this all returns like a boomerang in modern Japanese pop culture. Whether in the anime Natsume Yūjinchō, where a spiritualist cat predicts weather and the moods of gods, or in the manga Neko Ramen, where lunchtime depends on a meow. Edo Japan had its clocks — and its guardians of time. And one of them, as it turns out, was an ordinary cat. Apologies — there are no ordinary cats.
In a world where time was not only counted but felt, the sky and calendar served Edo-period Japan as sources of both order and mystery. Overseeing the passage of seasons and the precision of the calendar was the Astronomical Bureau (Tenmonkata), an institution no less serious than the tax office — though it dealt with stars, not coins. It determined solstice dates, adjusted leap months, and organized the rhythm of social life in accordance with the lunisolar-seasonal calendar, which had to be periodically aligned with the whims of the moon. Yet murmurs grew louder — especially among the educated — that the long-used Chinese model simply didn’t fit Japan’s realities. The weather was different, the latitude was different, and the times were changing.
So people began looking to the sky not only with spiritual reverence but also scientific precision. They observed stellar transits, measured local time and latitudes, and slowly — though still respectfully — the conviction emerged that time might be a mathematical abstraction, equal for all, independent of the shadow of a pine or the ringing of a temple bell.
Then came the year 1873 and, with it, an imperial edict that swept away the poetry of the old hours with a single stroke of administrative ink. Variable Japanese time — futei-ji — was abolished, and in its place came the Western, Gregorian, time-zoned, 24-hour system. The temple drums fell silent, clocks no longer tracked the sun and moon, and noon was no longer announced by a bell… but by the blast of a cannon. It was modern. And loud.
But not everyone was thrilled. Witnesses to this revolution — such as Ernest Satow or Rudyard Kipling — noted with some surprise that, although Japan had officially adopted European time, its people still didn’t take punctuality too seriously. When an appointment was set for two o’clock, the guest might arrive at one — or at three. It depended on the season. Old habits do not vanish in an instant.
And though today Japanese punctuality is legendary, with train departures measured in fractions of a second, the echo of the old rhythm can still be heard. Every day at 5:00 PM, when the gentle melody of Yuyake Koyake drifts across the cities, children return home, and the sun dips low on the horizon. Within that simple tune lies more than nostalgia — it holds the memory of an era when time was sound, light, ritual, and a sensory experience. And though the clock no longer follows a cat’s pupil or pauses at the Hour of the Tiger, something from old Japan still ticks — softly, persistently, in its own way.
>> SEE ALSO SIMILAR ARTICLES:
Machiya: What Were the Townhouses of Edo Like? – The Lives of Ordinary People During the Shogunate
Your Time is Your Space, Not a Frantic Race – 5 Japanese Lessons on Managing Your Own Time
Katakiuchi – A License for Samurai Clan Revenge in the Era of the Edo Shogunate
The Unidentified “Utsurobune” Object in the Time of the Shogunate – UFO, Russian Princess, or Yōkai?
未開 ソビエライ
An enthusiast of Asian culture with a deep appreciation for the diverse philosophies of the world. By education, a psychologist and philologist specializing in Korean studies. At heart, a programmer (primarily for Android) and a passionate technology enthusiast, as well as a practitioner of Zen and mono no aware. In moments of tranquility, adheres to a disciplined lifestyle, firmly believing that perseverance, continuous personal growth, and dedication to one's passions are the wisest paths in life. Author of the book "Strong Women of Japan" (>>see more)
"The most powerful force in the universe is compound interest." - Albert Einstein (probably)
未開 ソビエライ
An enthusiast of Asian culture with a deep appreciation for the diverse philosophies of the world. By education, a psychologist and philologist specializing in Korean studies. At heart, a programmer (primarily for Android) and a passionate technology enthusiast, as well as a practitioner of Zen and mono no aware. In moments of tranquility, adheres to a disciplined lifestyle, firmly believing that perseverance, continuous personal growth, and dedication to one's passions are the wisest paths in life. Author of the book "Strong Women of Japan" (>>see more)
"The most powerful force in the universe is compound interest." - Albert Einstein (probably)
___________________
Would you like to share your thoughts or feedback about our website or app? Leave us a message, and we’ll get back to you quickly. We value your perspective!