2/22 & the Relationship between Cats and Ninja

February 22nd is a special day, as it is a day of recognition for 2 separate themes in Japan. The first one is “Neko no Hi” (猫の日), or “Cat’s Day”¹, which has been around since 1987. The second is “Ninja no Hi” (忍者の日), or “Ninja Day”², which started in 2015. In this post I will pay tribute to both by introducing a topic that relates how cats were useful to the ninja.

There is a method for telling time called “neko no medokei” (猫の眼時計), or “cat’s eye clock”. During a time with no electricity and dependency was on the light from the sun, people in the past could use this method to tell the time by looking at a cat’s eye and observe how the pupils adjust based on the position of the sun. This is considered a special method used by ninja when they were active during middle ages in Japan. A few points to keep in mind regarding this is that while the method is indeed old, it was not originated by ninja, nor was it only used by them.

The concept behind the neko no medokei actually comes from a set of documents written in China in the year 860 called “Yūyō Zasso” (酉陽雑俎, Yŏu yáng zá zǔ in Mandarin Chinese). Within this text is a mixture of educational lessons and bizarre stories. Physical traits, coupled with some odd interpretations, regarding cats and their behavior with their eyes, nose, ears, and so on are included in this. Eventually, this text was brought over to Japan during the cultural exchanges in Japan’s earlier history, with the information on cat’s eyes being the inspiration to using it as a method for telling time. Of course, as with many things that have been adopted into their culture, the Japanese would put their own spin on it in order for it to fit with their culture and needs…this includes the ninja as well.

The poem regarding neko no medokei from the Mansenshukai

There is an old text called Mansenshukai (万川集海), which is considered one of the 3 important manuscripts of the ninja³. Within this text is a section called “Tenmonben” (天文編) which details information regarding weather conditions, operating at night, and telling time. There is a poem that describes how the neko no medokei works, which goes as the following:

「猫眼歌二 六ツ丸ク 五七ハタマコ 四ツ八ツ柿ノ實二て 九ツハ針」

“nekome uta ni mutsu maruku itsutsu nanatsu wa tamago yotsu yatsu kaki no mi nite kokonotsu hari”

Although written in code, this poem states simply the different shapes a cat’s pupils would undergo, which is related to the time of day based on sunlight. The details work according to the old clock system used before modern times, which incorporates the Zodiac signs from the Lunar calendar to indicate the specific hour(s) in a day. Here’s a breakdown of the poem:

  • Mutsu (六ツ) refers to the 6th hour of both the morning and evening, which would be at dawn and sunset respectively. At these times, a cat’s pupil will be a circle shape since dawn occurs before sunrise, and evening should arrive after sunset.
  • Itsutsu (五) represents modern time range 6~8 in the morning, and nanatsu (七) refer to 3~5 in the afternoon. A cat’s pupil will become an egg shape as sunlight is nowhere near being its brightest.
  • Yotsu (四ツ) represents modern time range 9~10 in the morning, while yatsu (八ツ) refers to 1~2 in the afternoon. A cat’s pupil will look like the shape of a persimmon seed as outside is pretty bright.
  • Kokonotsu (九ツ) represents the time around 12 pm, where the sun is at its brightest. Due to how bright outside is with the sun being at its highest point, a cat’s pupil will become thin and look like a pin.

Prior understanding of how to read this old clock system was critical in deciphering this poem in the past, although nowadays there are plenty of sources that explain it. Visually there are diagrams that interpret the details very clearly, such as the ones presented below.

One would imagine that the neko no medokei would’ve been useful for those who stayed in one location. While it is claimed that a ninja could use this while on a mission, most likely this would’ve been so during the day, for the neko no metokei wouldn’t be effective at night.

For those who own a cat could test this time reading method and see if the results are the same as above. If I did, I totally would give this a shot!

1) One of the reasons February 22nd was chosen as Neko no Hi is because the number 2 is pronounced as “ni” (nee) in Japanese. It is said that if you say just the numbers that represent this date as “ni-ni-ni” fast, it resembles the sound a cat makes.

2) One of the reasons February 22nd was chosen as Ninja no Hi is because of how the number 2 sounds close to “nin”, which is one way to say the word “忍” (nin, perseverance) and is usually associated with the image of ninja especially in pop culture. Basically, if you say just the numbers that represent this date as “ni-ni-ni” fast, it sounds like you are saying “nin-nin-nin”, which is like a shorthand of saying ninja.

3) These 3 are the following: Mansenshūkai (万川集海, also called “Bansenshukai”), Ninpiden (忍秘伝, also called “Shinobi Hiden”), and Shōninki (正忍記). Together, these are often categorized as “sandai ninjutsu densho” (三大忍術伝書, the 3 great secret texts of ninjutsu) in Japanese.