The Days of the Week and Japanese Kanji

Classical Astrologers hold the view that the Enlightenment brought about a profound shift in sensibility that was detrimental to the craft of astrology.  While many of us would accept this as a matter of course, we have been educated within the matrix of post-Enlightenment thought.  There are two assumptions that seem to be particularly difficult to overcome: 1) that the test of astrology is whether it “works”, or more specifically, that we can demonstrate that the movements of the planetary bodies have a demonstrable effect on our material existence; and 2) that astrology was “discovered” by Ancient scientists through observation of the material world as Modern scientists “discover” natural phenomena.

The second assumption must fall to the wayside when we consider the planetary rulerships for the days of the week.  Planetary Lords and Ladies of the Day are used in many different contexts in Classical Astrology, such as horary and electional work, and in calculations such as the Almuten Figuris.  Despite this, even though there is arguably a physical basis to a seven-day week (seven-days being roughly the quarter cycle of the Moon), I can not see that there is any plausible argument for a purely physical basis for the planetary rulerships of the specific days.

There is a discernible pattern in the assignment of rulerships to the days of the week, starting with the Sun and the Moon, and moving outward on an alternating basis from each of these luminaries.

Sunday                                       Monday (Moon)

Tuesday (Mars)                          Wednesday (Mercury)

Thursday (Jupiter)                      Friday (Venus)

Saturday (Saturn)

To be honest, I can only speculate on the reason for this pattern; however, it is very likely to be a spiritual and metaphysical reason, and not a physical one.  Interestingly, during the Enlightenment, in the West, there there were Protestants, such as the Puritans and the Quakers, who stripped the days of the week of their planetary correspondences to remove the “pagan” influences.  Quakers today still use numbered days, such as First Day and Second Day.

The planetary correspondences for the days of the week seem to transcend cultures.  One finds the same associations for the day of the week in Eastern religion and philosophy as in the West.

Recently, I have been immersed in the study of the Japanese language.  Japanese has three different sets of characters for writing.  There are two phonetically based “alphabets,” hiragana and katakana.  In addition, there is a third set, kanji, which are symbolic characters derived from Chinese writing.  Japanese school children are expected to learn around 2,000 different kanji by the time they graduate high school.  Among the earliest kanji learned by Japanese school children are the ones for the days of the week.

In Japanese, the days of the week are named for the Sun and the Moon, and the five Eastern elements.  The Eastern elements are not the same as the Western system of material elements, but instead directly correspond to the five non-luminary planetary principles.

kanji for week
kanji for day of the week

The kanji for each day of the week is made up of three characters.  The ending character is 日, which is the kanji for both the Sun and for day.  This is very similar to the Western solar glyph, except in this writing system, the glyphs are squared off.  The middle character is quite fascinating.  It is 曜.  As the reader can see, the kanji for Sun is included as a radical in this kanji to the left.  According to Essential Kanji, by P.G. O’Neill, the English name for the radical at the bottom is “small bird,” and the English name for doubled radical above it is “wing.”  There is another kanji that also contains the “small bird” with 2 “wings” on top.  This kanji is 躍, yaku, odo, which has a meaning of leap or jump, which includes the radical for “foot” instead of the radical for the Sun.  It seems that one could interpret the kanji for day of the week as something similar to “the flight of the Sun.”

The first character in the kanji for each day of the week is the kanji for the luminary or Eastern element for that day.  In Japanese, Sunday (the Sun’s Day) is nichiyoubi, or 日曜日.  As the reader can see, the character for the Sun is the first character in this kanji.

Monday (the Moon’s Day) is getsuyoubi, or 月曜日.  The kanji for the Moon looks a bit like the Sun on legs, which fits well with the light of the Moon being the reflection of Solar Light.  Astrologers are well aware of the Moon as the governess of the most intimate details of our physical existence.

Tuesday (Mars’ Day) is kayoubi or 火曜日 (Fire Day).  In the Eastern system, fire has a direct correlation to the Martial principle.  The kanji for fire contains the radical 人 in the center, which is also the kanji for hito, person, and nin, the counter for people.  There is a mark on either side of the person.  The Martial principle is closely associated with the duality of manifestation and choice and conflict.  Mars is also closely associated with will and Free Will, and is the first planet whose orbit is independent of the Sun’s.  See also Kanji Symbols-Fire, Movement, and Humanity

CaduceusWednesday (Mercury’s Day) is suiyoubi or 水曜日(Water Day).  In the Eastern system, water has a direct correlation to Mercurial principle.  This correlation may seem a bit less obvious than the association of Fire with the Martial principle; however, it does make sense upon further reflection.  Metaphysically, water is the most malleable of the elements, and is considered the “all possibility.”  There is an interesting similarity between the Hermetic symbol of the Caduceus and the kanji 水.  Also, the kanji for the metal mercury, suigin, is 水銀, which is literally, “water silver.”

Thursday (Jupiter’s Day) is mokuyoubi or 木曜日 (Wood Day).  Wood is associated with the Jovial principle.  The character at the beginning is 木, which is the kanji for tree.  As an aside, one of my favorite words in Japanese also contains the radical for tree in it.  The word is komaru or 困る.  The word is does not have a precise English translation, but it means being stuck, confused, or unable to move or proceed.  The kanji has a tree in a box, unable to grow.  In a sense, when the Jovial principle is blocked, we often become komaru.

Friday (Venus’ Day) is kinyoubi or 金曜日(Gold Day).  Gold, or Metal, is associated with the Venusian principle.  The first character in the kanji, 金, is the same as the kanji for kane,  or money.  The Venusian association with material wealth, prosperity, and money is a strong one.  Sri Lakshmi, of the Vedic tradition is strongly associated with both material wealth and the Venusian principle.

Lastly, Saturday (Saturn’s Day) is doyoubi or 土曜日 (Earth Day).  Earth is the Eastern element associated with the Saturnine principle.  In the kanji for Earth, 土, the cross of matter is firmly planted on the ground.  This symbol is strikingly similar to the glyph for Saturn, with the cross of matter on top of the lunar soul.  Also of interest is that the kanji for the number ten 十 is also the cross of matter.

I am still very much a novice in the study of Japanese.  There are calligraphers and sages of great wisdom that devote their lives to the study of the mysteries of kanji.  Yet, it seems there is profound metaphysical wisdom even in the very basic kanji learned by Japanese elementary school children, as can be seen in the kanji for the days of the week.


I just had a conversation with my Japanese Sensei (“Teacher”), and it seems that the names for the planets are the same as the Eastern elements and the days of the week, so:

Mercury is suisei, or 水星 (“Water Star”)

Venus is kinsei, or 金星 (“Gold Star”)

Mars is kasei, or 火星 (“Fire Star”)

Jupiter is mokusei, or 木星 (“Wood Star”)

Saturn is dosei, or 土星 (“Earth Star”)

7 thoughts on “The Days of the Week and Japanese Kanji

  1. Myriam, this is a very fine article on a fascinating topic. The flight of the Sun is far more resonant than *days oft the week* I’m also intrigued by the easy association of Mercury with water — the planet and the element are in fact the most fluid and malleable … food for thought

    1. Thank you for your kind words. Yes, isn’t the flight of the Sun a beautiful image! Yes, the association of water and Mercury is really interesting. Of all of the elemental associations, that is the one that was the most surprising when I learned it…but then, when I thought about it, it made a lot of sense.

  2. How interesting that the planetary coorespondences in the East are the same as those in the West! I would not have expected this, but it demonstrates that metaphysical principles are universal, rather than limited to any particular culture.

  3. Actually the truth about the Eastern and Western correspondence of the planetary days of the week is not that beautiful. First of all the Japanese names of days, planets and everything based on astrology are almost the direct reap-off of Chinese, even if they sometimes claim different due to strong buildup of legends.The Chinese signs for planets do have correspondences to the 5 changes (aka Chinese elements) these planets rule in Chinese astrology, yes. Hence Mars was simply a “star of fire” (火星) and so on. But the idea to name the days of the week the same way – e.g. “the day of Mars/fire” was not of Asian origin, but was done under the influence of Western style. It is a PURE ADAPTATION OF WESTERN TRADITION. Quite modern calendar change also. It would be actually hard to imagine that these two tradition came up with the same arrangement when they never agree to the tee with any kind of arrangement of symbols with the Western tradition. And everywhere one sees too vivid similarities in different cultures, one always suspects the influence first.

    1. Thank you for your comment, Mr. Rozek. Yes, it is true that the modern Japanese calendar includes a fair amount of cultural assimilation, with an interesting mixture of Western and Chinese. It uses the Chinese labeling of the years, yet the New Year starts on January 1. It is also true that there are different cultural systems of dividing week. The traditional Eastern calendars used different weeks for different purposes, including a system based on lunar mansions, see Interestingly, though, the seven-day week was used for astrological purposes long before Japan adopted the Gregorian calendar during the Meiji period reformation.

      There is a less well known Japanese elemental system, known as the 五大, godai, or “5 Great” Elements that corresponds almost directly with the Western 5 elements, see

      Even though cultural assimilation exists, it is much more complicated than one culture copying another. Japan is particularly interesting in that regard, because unlike China, Japan was able to take in Western culture on its own terms (even under the extraordinary circumstances of being invaded and bombed with nuclear weapons).

      1. Yes, this is interesting too. Though my belief is that modern Japanese folks rather come into contact with Japanese adoption of Xiu – that is the Chinese lunar mansions – when they are really into old books on old tradition. The five “elements” is usually all that is alive in common culture. Maybe the 五大, but it didn’t ever look deep enough to dig on that.
        And I am to astonished how Japanese see no problem of mixing elements of Christian, Buddhist, Shinto, capitalistic, theatrical and vulgar culture almost at random and don’t see it as a problem. And for some reason they have been having this jealousy of West complex (if I may say so, hoping no sensitive Japanese would come here). I was pondering once, is it maybe do the the way they language is constructed? They use the 漢字 signs borrowed from China, some together with the way of pronunciation. But they also had their own indigenous versions of these words. They ended up mixing the two methods, and such stuff, perhaps in the language & culture envy they tried to make their culture so complex so it would be not possible to say that they are a strict adoption of Chinese things. Even West bombing them could be a subconscious inspiration: Oh, they are nowhere to compare with Chinese, let’s mixed some of their stuff in our culture! :)

      2. I think that this is really one of the biggest differences between the Eastern and the Western way of thinking. This difference can be seen in Classical medical texts from the East and the West. In Eastern medical texts, great effort would be taken to show how different schools of practice were similar and congruent. In Western medical text, the same effort would be taken to show and explain the differences between schools of practice. Eastern thinking tends to focus on agreement and consensus, whereas Western thinking tends of focus on discord.

        I think that the Japanese assimilation of Western culture is a complex issue, with many different factors. On the other hand, by assimilating some Western culture voluntarily, Japan was able to retain much of its own culture and wisdom, and to choose for itself what it took in and what it did not.

        Here is an interesting article written which talks about different ways of viewing the West and Western culture…all in one family:

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