In the cool breeze of the eighth or ninth lunar month, at the western end of Chang'an, the Imperial Secretary He Zhizhang hosted a lively banquet at his mansion, filled with honored guests. Amidst the revelry, the host rose to welcome a new arrival, and everyone saw a young monk standing at the hall's entrance.
“Who is that monk?” the guests whispered among themselves. “A monk at a drinking party?” “He is Huai Su, a disciple of Master Xuanzang,” someone explained. “He takes monastic vows but does not abstain from wine, and his cursive calligraphy is unmatched. From his hometown of Changsha, nearly every notable household in Hunan’s seven prefectures has one of his hanging screens.” After several rounds of wine, He Zhizhang rose to toast the guests and said, “On such a fine gathering, we must have poetry to enliven the mood. May I invite the Immortal Banished from Heaven, Academician Li Bai, to compose a piece in honor of this occasion?” Li Bai did not decline but replied, “Poetry springs from inspiration. The wine has stirred me, but it is not enough. I would ask Master Huai Su to perform his calligraphy before us to further fuel the poetic spirit.” He Zhizhang said, “I know that Reverend Huai Su’s ink flows best when he is tipsy. Attendant, pour more wine!”
While Huai Su drank freely, his attendants carried out several chests of hemp paper and plain silk for writing, and arranged several fine Xuanzhou inkstones on the desk, with servants taking turns adding water and grinding ink.
Huai Su set down his wine cup and rose gracefully, and the hall fell into immediate silence. The young monk picked up his brush, dipped it in ink, and fixed his gaze on the paper for a moment. Then, with a sudden burst of energy, he swept the brush across the silk, his arm turning and wrist spinning, finishing sheet after sheet. In no time, the floor was covered with wildly spirited cursive script, and several chests of fine paper and plain silk were completely used up.
When Huai Su threw down his brush and returned to his seat, Li Bai's "Song of Cursive Script" was already written. He recited aloud before the crowd: "Young master Huai Su, your cursive script is unrivaled under heaven... My teacher, after drinking, leans on a rope to rest... Rising, he writes without stopping, each line of characters as large as a dipper, startling gods and ghosts, and at times one sees dragons and serpents darting..."
He Zhizhang commented, "The master's calligraphy swirls left and coils right, truly like dragons and serpents dancing! Fine writing, fine poetry!"
The calligraphy of Huai Su, the poetry of Li Bai, and the commentary of He Zhizhang—these three talents once swept through the capital like wildfire, their works celebrated in every corner of Chang'an.
"The idiom 'brush strokes like dragons and snakes' thus became a phrase describing bold and free-flowing calligraphy."
Source: *Li Taibai Collection*, "Song of Cursive Calligraphy"
Meaning of the Idiom: Later, the Chinese idiom "笔走龙蛇" came to describe brush strokes like dragons and snakes.