The Dragon Boat Festival was considered an "evil day" in ancient times.

The fifth month of the lunar calendar corresponds to the three Earthly Branches of "Si," "Wu," and "Wei," all belonging to the Fire element. "Si" represents the birth phase of Fire, "Wu" represents its peak, and "Wei" represents its decline. When Fire energy reaches its peak, meaning Yang energy reaches its peak, it will reverse course and Yin energy will begin to emerge.

According to the "Records of the Grand Historian," Mengchangjun Tian Wen was born on the fifth day of the fifth month. His father once ordered his mother to abandon Tian Wen. The Eastern Jin general Wang Zhen'e was also born on the fifth day of the fifth month, and his grandfather named him "Zhen'e." This suggests that the ancients generally considered the fifth day of the fifth month an unlucky day. Therefore, it's natural to plant calamus and mugwort to ward off evil spirits, fumigate with Atractylodes lancea and Angelica dahurica, and drink realgar wine to ward off epidemics.

Around the transition between solar terms, the aura is at its most unstable, easily causing anxiety, leading to legal troubles and disasters, and the proliferation of diseases, all of which can affect one's fortune.

The fifth day of the fifth lunar month marks the beginning of May. Yin energy begins to build and gradually intensifies, marking the peak of Yang energy and the beginning of the transformation between Yin and Yang. The Tai hexagram in the Book of Changes represents the first month of the year, and its ultimate form is the Qian hexagram (all six Yang lines) representing April. On the fifth day of the fifth lunar month, "Tai reaches its extreme, and Fei arrives." Therefore, the ancients attached great importance to this transformation and employed methods to dispel Yin energy, ward off evil spirits, cultivate restraint, and cultivate a sense of quiet, thereby removing any ominous aura.