Cinco de Mayo is also Boys’ (or Children’s) Day in Hawaiʻi

So if you see these fish flags, you know why.

While plenty of bars and restaurants throughout Hawaii will break out the Dos Equis, chips and salsa for today’s Cinco de Mayo holiday, many family homes will celebrate May 5 a little bit differently: by flying koinobori, colorful carp-shaped flags, in honor of Tango no Sekku, or Boys’ Day.

The traditional Japanese holiday’s original intent was to honor and recognize all male children on the fifth day of the fifth month, a corollary to Girls’ Day, which honors female children on the third day of the third month (March 3). In recent years in both Japan and Hawaii, however, there has been a push to combine both Girls’ and Boys’ Days into one all-encompassing Children’s Day celebrated on May 5. Perhaps because it has been a longstanding tradition here, the individual holidays are often still recognized in Hawaii.

Males whose families and friends celebrate Boys’ Day can expect to receive special attention on May 5. Popular gifted treats include kashiwa-mochi, a rice cake made with the sword-shaped leaves of an iris plant thought to ward off evil spirits and have healing powers, and chimaki-mochi, a similar cake wrapped in bamboo leaves. Within Japanese American homes, the day often also includes a display of masculine heirlooms like swords, bows and arrows, as well as musha-ningyo, armor-clad samurai Boys’ Day dolls.

If you happen to drive through a neighborhood in Hawaii today, look for the carp windsock streamers “swimming” the trade winds from bamboo poles in front of houses. Carp are a classic Japanese symbol associated with strength, perseverance and longevity. In the wild, the fish swim against currents, scale waterfalls and can live a very long time—fitting qualities to emulate. Traditionally, each streamer represented a male in the household—the carp nearest the top of the pole usually symbolizes the father and is the largest, followed by the sons ordered by age. In more recent years with the onset of Children’s Day, additional carp have also been included and flown to honor the home’s mother and daughters.

From Hawaii Magazine: ¡Ole! And, Happy Boys’ and Children’s Day!