"A great pianist can mimick the sound and image of a mist arising from raindrops splashing on the ground. A guqin evokes the sound and image of a mist deep in mountains," he says.
Guo, 47, was not pitching piano against guqin as if one was inferior to another. In fact he's a connoisseur of piano and many other musical instruments, Chinese and Western.
But as a tai chi master, he says only guqin is the musical equivalent of tai chi. "Tai chi and guqin are both inherently like a mist. Their power springs from their softness."
A piano key usually produces only one note, often with a short lingering sound, but a guqin string has 13 major notes and each note has many variations depending on subtle finger movements. In several tests of frequency spectrums, Guo found that a guqin has a much longer lingering sound than a piano, a violin or a harp.
"Even if your ears can't hear it, a guqin's lingering sound, measured by its frequency spectrum, resembles that of a cannon," Guo says.
He is one of a group of people in Shanghai who, having weathered the vicissitudes of life, are now enchanted by guqin, a 3,000-year-old seven-string Chinese zither, for its capacity to capture and captivate the heart of a hermit enlightened in Confucian and Taoist values, especially those that encourage man to be at one with nature and at ease in adversity.
For thousands of years before the "cultural revolution" (1966-76), guqin was a favorite, indeed soul mate, of most Chinese scholar-officials and men of letters.
Confucius (551-479 BC) was a great guqin player and was said to be the author and composer of China's first guqin song, titled "Orchid," in which Confucius, whose moral teachings then fell on the deaf ears of most state leaders, compared himself to a noble orchid left untended and mixed with wild grass at the roadside.
Wang Wei (AD 701-761), a great Confucian scholar-official of the Tang Dynasty (AD 618-907), was dubbed China's poet Buddha for his devotion to Taoist and Buddhist meditation, particularly in the latter half of his life.
One of his popular poems pictures himself in a state of retreat. Here's my tentative translation:
Alone I sit in you huang li,
Plucking the strings of my qin.
In joys and sorrows I sing,
Yet who will understand me,
But the moon clear and clean?
In Wang's time, guqin was called qin. Gu, literally meaning "ancient," was added in modern China in reference to its history. You huang li literally means "a deep and quiet bamboo forest."
Be it with Confucius or Wang Wei, guqin was more than just a musical instrument. Its graceful tone -- often soft, remote and merrily melancholy -- meshes well with Confucian values of moral integrity and mental balance.
For that reason, Confucian scholars in the Eastern Han Dynasty (AD 25-220) regarded guqin as a moral force against obscenity and extravagancy. The "cultural revolution," however, swept guqin into historical oblivion along with Confucian thoughts -- both were downtrodden as part of "decayed feudal culture."
"At that time, you could only play guqin in secret. Once found, your guqin would have to be thrown into the fire," recalled guqin master Qiao Shan, who is now art director of a nice guqin school named after you huang li and seated in a quiet French-style building in the roar of Shanghai.
Only one year old, the school on Huaihai Road has attracted nearly 500 students. It will open a branch in Pudong New Area at the end of this month in the midst of a quiet revival of guqin culture in the city.
It's "a quiet revival" because the number of guqin fans are still dwarfed by piano or violin fans not just in Shanghai, but across China.