The Fall celebration called “Jūsanya” (十三夜, Thirteenth-Night Moon)¹ will be taking place on 10/23 this year. An otsukimi (お月見), or moon-viewing occasion embedded in Japan’s history, people often light traditional lanterns such as chōchin (提灯) and andōn (行燈)² at home or in local festivals, and enjoy a serene time observing a not-so-full moon while consuming snacks such as tsukimi dango (moon-viewing dumplings), kuri (chestnuts), daizu (soybeans), satoimo (taro), and seasonal sweets. While it may be thought of as a night of the full moon, in truth the moon’s phase is the one right before that, generally called “jūsanya tsuki” (十三夜月, waxing gibbous moon) in Japanese.

Actually, there are multiple moon-viewing celebrations, with the larger being Jūgoya (十五夜, Fifteenth-Night Moon), which takes place about a month in advance³ around the time of a full moon, and is a time where gratitude is given to successful harvests. Jūsanya, on the other hand, is a later festive event. Along with timing being off, the moon phase is generally not quite a full moon. Yet, the Japanese still see value in it, as they have a believe about appreciating things that aren’t quite in perfect form, as these things also have their own unique beauty.

There is an interesting story that is tied to Jūsanya, which conceived a traditional festivity held with pride in Kagoshima Prefecture. This all entails the heroic acts of the warring hero known as Shimazu Yoshihiro (島津義弘).

DESPERATE CHARGE TO RETURN HOME

On the 15th day of the 9th month of 1600⁴, the battle of Sekigahara was taking place. Shimazu Yoshihiro was present during this as the commander of the Shimazu army from Satsuma Province (present-day western part of Kagoshima Prefecture), and was fighting on the side of other allies on the western force led by Ishida Mitsunari. To claim ultimate control over Japan, this western force was clashing with opposing supporters and armies of the eastern force led by Tokugawa Ieyasu. After several hours of conflict, the western force suffered several huge losses due to unforeseen events, which was a sign of their impending defeat. It is said that Yoshihiro made a decision not to go down fighting, but to retreat his army and head back to their homeland. However, there was no escape route in sight, as they were potentially surrounded by their opponents. With no other options, he commanded his allies to break through with force.

Following their commander’s orders, the Shimazu army rushed forward and collided with enemy armies, taking out whomever stood in their way, and sacrificing themselves for the sake of their commander’s survival. As suicidal as is sounds, their desperate charge was actually parting the opposing armies, for they were not prepared for such an action. Soon, they came upon the main army of the Tokugawa, which was the greatest threat to their existence. Without losing a beat, the Shimazu army pushed their way through as well, not letting this threat deter them as they created the exit they needed⁵. Ieyasu commanded his troops to give chase, but in the end they could not capture Yoshihiro nor stop the Shimazu army.

Putting distance between them and the battlefield, Yoshihiro and his remaining troops made their way to the temple Byōdōji within Mt. Miwa in Nara Prefecture for refuge, and remained hidden there until they could make a safe journey back to Satsuma Province on the 28th day of the 11th month of the same year. This event is often referred to as “敵中突破” (tekichū toppa), or “breaking through enemy lines”.

NIGHT PILGRIMAGE UNDER THE (NOT QUITE) FULL MOON

Shimazu Yoshihiro’s decision to retreat during the battle of Sekigahara was an important one, which secured the future of Satsuma Province as a whole. For starters, his homeland sat in a unique position, as Satsuma borders the far most western tip of Japan, which puts it in an advantageous area and makes the region difficult to invade⁶. The Shimazu clan and many warriors hailing from Satsuma have a reputation as exceptional warriors, with fairly good results under their belts. Furthermore, the people of Satsuma held onto many cultural traditions much longer than the rest of Japan, which also includes the principles of bujutsu and the way of the warrior which would survive up to the later period of Edo period. If Yoshihiro and the Shimazu army were to have fallen during that battle, the future of Satsuma may have been a bleak one, where it could’ve fallen in the hands of the Tokugawa shogunate. Even if Yoshihiro himself was captured, he would’ve most likely faced punishment by death, which many who were on the western force ultimately received.

During the peace brought under the Tokugawa shogunate in Edo period, future generation started a tradition on the anniversary (9/14) of this battle in recognition and gratitude to Yoshihiro’s bold charge to return home. Young warriors from Satsuma would group up near Kagoshima castle, don on full armor and other gear, and take a nightly pilgrimage from there to the temple Myōenji in a town named Ijūin (伊集院), where they made prayers before a statue of Yoshihiro himself. The journey was truly a long one, for the distance they crossed is recorded to be 40 km (almost 25 miles!). This event made by these warriors was given titles such as “満月参り” (Mangetsu Mairi, Full moon Pilgrimage) and “伊集院の満月参り” (Ijūin no Mangetsu Mairi, Full moon Pilgrimage to Ijūin), since they chose to walk in the illumination of a full moon above them…but in reality this was a not-so-full moon. This point is important to remember, for the date given for both the battle of Sekigahara and the anniversary is based on the old calendar, and is closer to the time of what we would call today Jūsanya. The period of a full moon related to the time of harvest was actually, according to the old calendar, the previous month (on 8/15, which was the date of Jūgoya). Despite the timing being off, these individuals still view the moon as being “full”.

MODERN ADAPTATION

In present times, the pilgrimage falls on the 4th Saturday & Sunday of October of each year, which aligns with Jūsanya. Note that this procession in honor of Shimazu Yoshihiro has undergone a couple of changes. The first being the name change to “Myōenji Mairi” (妙円寺詣り, Pilgrimage to Myōenji ). The next few changes are due to circumstances, such as the starting point is designated to the shrine Terukuni Jinja in Kagoshima city, and participants walk a distance of 20 km (12.5 miles) to another shrine called Tokushige Jinja, and pay respects to Shimazu Yoshihiro’s statue.

Why these changes? For starters, Terukuni Jinja is a shrine that reveres the prominent figures of the Shimazu family that contributed great accomplishments, making it an excellent spot for good luck. Next, the distance became shorter due to both shrines’ physical positions, making participation both more accessible and festive. Lastly, Tokushige Jinja sits in the original spot where Myōenji was after it was burned down, and hosts the Yoshihiro’s statue. Myōenji still exists, as it was rebuilt not too far away from Tokushige Jinja, but Yoshihiro’s statue was not returned back despite the name used for the pilgrimage.

ENDING

While Jūsanya may not have the same appeal as the preceding Jūgosan, it is tied to significant events. While for some it is a night for moon gazing and enjoying the moment, but to others it’s a time to honor one of Japan’s heroic figures. Hope this article could be both enjoyable and provide insight on how deep & intricate some Japanese traditions can be.

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1) Also known as Nochi no Tsuki (後の月, the Late Moon), since it was the later moon-viewing event of Fall. Other names include Kurimyō-Getsu (栗名月) and Mamemyō-Getsu (栗名月), in relation to the period for chestnuts and soy bean picking.

2) Chōchin is the paper lantern that is hung, very commonly used during public festivals, while andon are table lanterns.

3) While the gap is about a month’s difference, it would be wrong to say that it takes place in September. According to the old Lunar calendar, Jūgoya always fell on 8/15. However, due to how the modern Gregorian calendar works with leap days and such, the date is always changing. Here’s a 3-year comparison on how great the date shifts:

• 2025 = October 6, 2025
• 2026 = September 25, 2026
• 2027 = September 15, 2027

4) This is according to the old calendar once used in Japan. Following the modern Gregorian calendar, this date falls on 10/21.

5) Know in Japanese as “Shimazu nokiguchi” (島津の退き口, Shimazu army’s rear-guard retreat)

6) Satsuma Province did suffer from internal strife, as well as a couple of invasions, most unsuccessful. The only warlord successful in both defeating and subjugating the warriors of Satsuma was Toyotomi Hideyoshi.