Decoding Hokusai and Others in the Edo Era Calendars Challenge!

An exhibition titled Let's Decode Calendars by Hokusai and Others! is now on at the Sumida Hokusai Museum. Presented in two terms, the first ends on January 26, and the second runs from January 28 to March 2.

The exhibition outlines the creative ways in which Katsushika Hokusai (1760-1849) and other artists of his era, depicted calendars for the population of Edo. It is highly educational and a great deal of fun.

But first, for those unfamiliar with Japan, a considerable degree of background is needed.

The kanji of the Japanese numbers from one to twelve are 一 (1), 二 (2), 三 (3), 四 (4), 五 (5), 六 (6), 七 (7), 八 (8), 九 (9), 十 (10), 十一 (11), 十二 (12).

The Japanese months do not have names, as in January, February, etc. They are simply known as "second month" (二月), "fifth month," (五月), "eighth month" (八月), etc. However, January can also be written as 正月 with正 substituting for 一.

The Cycles of the Sun and the Moon

In Hokusai's time, Japan used the lunar-solar calendar. It subsequently adopted the Gregorian calendar, a solar calendar, in 1873, as a part of the internationalization of the Meiji era.

The lunar calendar is based on the cycles of the moon, which are 29.5 days. Six of the months of the year were therefore accorded with 29 days and six with 30. As 29.5 x 12 equates to 354. However, that is 11 ¼ days shorter than the 365 ¼ days that it takes for the Earth to circle the sun.

A twelve-month lunar year would rapidly take the months out of sync with the seasons. An extra month (intercalary month) was thereby added every two or three years. Its kanji character could be depicted as either 閏 (uruu) or 壬 (jin). The Japanese calendar took both the sun and moon into account, hence being known as the lunar-solar calendar.

The selection of the long and short months, and whether or not to include an intercalary month, was made by astronomers. It varied every year.

Creative Alternatives

An accurate calendar was essential for samurai, townsfolk, and farmers alike. There were an abundance of festivals and annual events within Edo era life. Moreover, goods were commonly bought on chit, with accounts being settled on the final day of the month.

The simple option would have been the distribution of calendars with the months in table form. But such simplicity was not Edo-era style. Instead, calendars were commonly produced pictorially. These calendars were known as daisho, dai (大) meaning big and sho (小) meaning small. They have subsequently become known as egoyomi, or picture calendars.

Images Created From Numbers

One popular form of picture calendar was a motif drawn with numbers. Tsuno Daishi, by an unknown artist, is an illustration of Heian period priest Ryogen. Legend has it that during a plague epidemic, Ryogen grew horns and drove out the disease.

The illustration is drawn with the characters, clockwise from the top, 正, 三, 八, 六, 十一 (1, 3, 8, 6, 11). 五 (5) represents the torso. After identifying the numbers, the year within which the illustration was produced can also be ascertained. January, March, May, June, August and November were the short months of 1786.

In a further form of illustrated daisho, the names of the months were drawn into the image. In Kintaro Feeding a Japanese Bush Warbler by Hokusai, the kanji for small (小) is rendered in yellow on the axe blade. The characters 正, 五, 六, 八, 十 and 十一 are written across the blade's tip. In 1799, January, May, June, August, October and November were the short months.

Months that are Suggested Rather Than Named

Daisho that are considerably harder to decipher are devoid of actual numbers. They contain verses that allude to specific months.

In Kagami-mochi and Sake Barrel, by an unknown artist, the first written verse uses the names of styles of mochi, a glutinous rice confection. These mochi types were served at holidays or events within specific months. For example, Lozenge (lozenge-shaped mochi) is offered in March when Hina dolls are displayed. Kashiwa (oak) implies kashiwa mochi, or oak-leaf mochi, which is identified with the Boys' Day celebration held in May.

The Meiwa era (1764-72) was the high point of daisho. They became so popular that parties were held in which they were exchanged. Hours were spent devising the most creative ways within which the long and short months could be depicted.

Their legacy can still be felt today. Japanese companies routinely produce calendars that are distributed to their customers and clients at the end of the year.

Try It Out

The exhibition concludes with a series of daisho that visitors are invited to decode. The most simple of them, Monkey Mask and Eye Mask, is below. Which mask contains the numbers of the long months and which those of the short? What numbers are used within the illustration of each mask? Please give it a try.