Koromogae Day: Seasonal Wardrobe Switch (Koromogae no Hi)

What Is Koromogae no Hi?

June 1st is "Koromogae no Hi" -- the day of "koromogae," the custom of switching one's clothing from winter wear to summer wear (and vice versa) with the change of seasons. Many schools and workplaces switch their uniforms to summer styles on June 1st and back to winter styles on October 1st, making koromogae one of the seasonal traditions that mark the rhythm of the year in Japan.

The Origins and History of Koromogae

The roots of koromogae trace back to a Heian-era (794-1185) court ritual called "koi," modeled on a Chinese custom. It was a practice of switching between summer and winter clothing to dress appropriately for each season.

• Heian Period: The imperial court practiced "koi," switching between summer and winter clothing on the 1st day of the 4th month and the 1st day of the 10th month (by the old lunar calendar).
• Kamakura Period: The seasonal change came to include not only clothing but also household furnishings.
• Edo Period: The shogunate formalized four changes a year: lined kimono (awase) from the 1st day of the 4th month, unlined katabira from the 5th day of the 5th month, awase again from the 1st day of the 9th month, and padded wataire from the 9th day of the 9th month (all lunar). Ordinary people followed this schedule as well.
• Meiji Period: After Japan adopted the solar calendar in 1873, the Western-style uniforms of government officials, soldiers, and police were set as summer wear from June 1st to September 30th and winter wear from October 1st to May 31st. This spread to school uniforms and then to the general public -- the direct root of today's practice.
• Today: Partly due to changing climate, the timing of koromogae has become more flexible, varying by individual and region.

Why "Koi" Became "Koromogae"

"Koi" (更衣) was also the title of court ladies who helped the emperor change clothes. Because the term later came to refer to a rank of court lady serving in the emperor's private quarters, ordinary people are said to have used the word "koromogae" instead. At court, even the fans that ladies carried were changed by season: hinoki cypress fans in winter and paper-and-bamboo fans in summer.

Modern Koromogae: When and What to Switch

Today, koromogae is mainly done according to personal comfort and local climate, but here are some general guidelines.

• Switching to Summer Clothes (late May to early June): Short-sleeved shirts, lightweight tops, linen fabrics, etc. Consider switching once daytime temperatures start to climb.
• Switching to Winter Clothes (October to November): Sweaters, coats, fleece, etc. Get ready once mornings and evenings start to feel chilly.
• Transitional Seasons (Spring and Fall): Long-sleeved T-shirts, light cardigans, trench coats -- layer pieces that can be adjusted as temperatures fluctuate.

Tips for Koromogae and Storing Clothes

• Wash Before Storing: Storing clothes with leftover dirt or body oils can cause discoloration, moth damage, or mold. Wash or dry-clean items before putting them away.
• Use Mothballs/Repellent: Wool, cashmere, and silk are especially vulnerable to moth damage. Since repellent vapors sink downward, place repellent on top of stored clothing.
• Use Compression Bags: Bulky items like blankets and sweaters take up much less space in compression bags (check care labels, as some materials such as down may not suit compression).
• A Chance to Declutter: Koromogae is a good time to review anything you haven't worn in over a year and keep your closet manageable.
• Guard Against Humidity: Place moisture absorbers in storage areas to prevent mold during Japan's rainy season (tsuyu).

Fun Facts About Koromogae

• In relatively cold Hokkaido, koromogae is often held half a month off, on June 15th and September 15th.
• In the warm Nansei Islands, including Okinawa and Amami, it often takes place on May 1st and November 1st, so the summer-uniform period is longer than on the mainland.
• The Japanese word for "changing room" (更衣室, "koi-shitsu") uses the same characters as "koi," the old name for koromogae, meaning "renewing one's clothing."
• "Koromogae" is a summer seasonal word (kigo) in haiku, referring to the early-summer change of clothes.

How to Spend Koromogae Day

• Carefully wash or dry-clean your winter clothes before storing them, so they're ready to wear comfortably again next season.
• Use koromogae as a chance to sell or donate clothes you haven't worn for a long time via secondhand shops or resale apps.
• Check your summer clothes, make a list of anything worn out, and plan replacements thoughtfully.
• Replace repellents and moisture absorbers with fresh ones to prepare your storage space for the rainy season ahead.

Dressing for the Season: An Expression of Japanese Sensibility

Koromogae Day on June 1st is about more than just switching clothes -- it's a way of living, dating back to the Heian period, that involves sensing the change of seasons and reorganizing daily life accordingly. As you slip into your summer clothes for the first time, take a moment to feel the refreshing sense of a new season beginning.