Shiwasu: How busy monks coincide with the last month of the year

Japanese can be a very colorful language, especially before standardization took place in recent times. Many words that have survived hundreds of years and is still part of modern speech due to their inclusion in the culture have some very interesting back stories. These can range from the name of towns, types of clothing, professions, or celebrations. One topic I’d like to bring up is the naming convention of the months within a yearly cycle, which was a project just recently finished. This can be found in the Translation section under “Topics Related to the Lunar Calendar”. Some points regarding the origins of how these months were named left a lasting impression on me, one particular I want to elaborate on just a little.

The characters for the 12th month name, Shiwasu. From Illust-AC.

According to the old Lunar calendar called “inreki” (陰暦)¹ once used in Japan’s past, each of the months have a “standard” name alongside which number month it is. They were also accompanied with many variants, which were devised with a relatable concept. These names are not as significant as they once used to be, but provide a cultural glimpse several hundreds of years ago of how people lived, how they viewed the seasons, or what activities were significant at specific times. Some are easy to understand and give you a clear visual once you hear the description. Others are not so clear, or have a description that may not really make sense at all. The biggest culprit of this is “Shiwasu”, which is designated as the 12th month of the year². The name Shiwasu has a unique meaning of “teacher (Buddhist priest or monk) rushing about”, which in turn indicates the ending of the year. How can such a description have any relations to indicating what month it is? And why a monk?  

Below are a few quoted sections from an article about Shiwasu, which comes from the website “Setagaya Byori”. It provides a few nice examples, and gives a slightly different take from my own write up in the project mentioned earlier. Below is the original Japanese text, followed by my English translation.


“The word “Shiwasu” was the designated label to the “12th month” of the old (Lunar) calendar from the very start. To be entirely clear, it points to the later part of the 12th month all the way to the earlier part of the 2nd month. However, it is more familiar to us as an alternative name for the 12th month within the new calendar.”


“The term “shi ga haseru” (師が走る), which means “teacher is hurrying about”, gives us vivid thoughts of a very busy end of the year. However, the characters used in this name is said to be an ateji (当て字), or alternative label for naming purposes only, for the explanation behind it doesn’t match up properly with the actual roots for the name.”


“The explanation for “shi” of “shiwasu” is that it stands for Buddhist priest or monk, and is a famous one as being the roots of its origin, which goes something like the following. During the winter season, monks were busy running back & forth from east to west because there were many homes that required Buddhist services, which included calling for a monk to recite sutras. Due to this practice, the term “shi ga haseru” was shortened to just “shihasu” (しはす). This explanation is based on the writing of the word “shihasu” in the late Heian period ancient dictionary called “Iroha Jiruishō”. It is thought that the characters “師走” were being referenced in the word “shihasu”, thus the origin for this explanation.  Another explanation is that “Shiwasu” accidentally became a word from the phrase “Shihase Tsuki” (師馳せ月), which shares the same meaning.”

Just by reading this, one can get an idea where some issues would pop up. One of the biggest is the pronunciation. Why change to “shiwasu”? Ease of pronunciation? Apparently in the Iroha Jiruishō only the phonetic “しはす” (shihasu) is written, with no indication that the characters “師走” is being referenced. One linguistic point here could be that, as witnessed in some older documents, the character ha (は) represented the sound wa, which may be why it was assumed that the reading should be “shiwasu” instead³. Unfortunately, there is no real evidence in this case that leads to such a point.

A monk hurrying along during the last month of the year. Is this truly the origin behind the name Shiwasu?!? From Illust-AC.

One thing worth mentioning is that studying up on Japanese history will show that there was a strong presence of Buddhism during the late Heian period, especially in Kyoto, where the Imperial palace was present throughout the majority of Japanese history. Many nobles also lived there, and kept up with what was popular, which including growing interest in Buddhist practice. Due to this, it is most likely that monks were busy fulfilling requests of visiting homes and reciting sutras. However, was this truly the basis for the naming convention for the last month of the year? Most likely not, especially since many other activities were taking place at the same time that may have been more significant. There is a strong belief that this is a more recent creation that puts a bit of poetic spin on the name, which would then spread and become popular. Fortunately, there are more solid theories behind the root word “shihasu”, which are stronger and closer to the actual end-of-the-year description. This can be read in the last page of “Months” here.

Here’s yet another theory that is interesting, for it supports a different spin on the busy religious teacher theme, but from a Shinto angle.


“There is another variation to the explanation regarding a teacher busily running around. It states that the character “shi” (師) comes from the title “onshi” (御師), which is a rank in Shinto tradition meaning “low level Shinto priest”. The story here is that during the winter season, onshi were very busy with tasks such as guiding worshipers who come to visit the shrine, and conducting prayer services…”

This is just one of the many different theories placed on this unique name “Shiwasu”. Unlike the Buddhist priest theory, the Shinto priest theory is not a popular one. On top of this, it is most likely a recent theory.

Honestly, researching about “Shiwasu” while working on the months of the Lunar Calendar project was one of my highlights that left me scratching my head all too often, but not entirely due to frustration. Oddities like this give a glimpse of some of the creative liberties with the Japanese language in the past that individuals took that shine a light on cultural aspects and topics. If I were to point out every word like this that I’ve come across over the years, I could write about each one in an article everyday for about a year!

1) The Lunar calendar coincides with what was used in most of Asia in the past. Compared to the western Gregorian calendar, the Lunar calendar has a different starting point by almost a month. That means that new years took place at the start of today’s February! Also, the length of each month varied due to certain conditions.

2) According to the Lunar calendar, this was most of what we would designate as today’s January. Japan has long switched to the Gregorian calendar, so Shiwasu begins at the 1st of December and ends on the 31st. On a side note, this adjustment actually affects the meaning of certain names, as they were originally designed to match up with corresponding seasonal changes.

3) Here’s an example of Japanese grammar for those interested. On page 69 in the 3rd volume of the Takeyazō-sho version of Iroha Jiruishō is the word “貫河”. The phonetic for this is written as “ぬきかは” (since it is an official documentation, it actually is written in katakana as “ヌキカハ”).

At 1st glance one would think that this is read as “nukikaha”, but in reality it is “nukikawa”. The reason is the character “河” is pronounced “kawa” as a standard. In the past the character “は” doubled for the sound “ha” and “wa” visually. Basically, you would have had to have been educated to know this point so as to not read it incorrectly depending on which word it was being used in.

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