That year, he was a 17-year-old student of American pianist Gary Graffman at the Curtis Institute of Music in Philadelphia. Later, Lang joined the Chicago Symphony Orchestra under the baton of Christoph Eschenbach for its Gala of the Century concert as a last-minute replacement soloist to play Tchaikovsky's first piano concerto.

After his performance during the gala, the young pianist was invited by other musicians to play more pieces. To their surprise, Lang played the complete Goldberg Variations for over an hour.

"When I told them that I would play Bach's Goldberg Variations, many musicians were like 'are you joking with me?' But after I finished playing it, they not only stayed awake but were also impressed," Lang recalls.

However, every time he decided to record Bach's Goldberg Variations for an album, Lang felt that he was not ready.

In April 2017, the pianist hurt his left hand and had to cancel his concerts for 15 months due to severe inflammation.

Feeling depressed and not knowing when he could return to the stage, Lang took a step back and began researching the Goldberg Variations from the scores to the ornamentations and recordings by other musicians during the hiatus.

Legend has it that Bach wrote the Goldberg Variations to help his friend Count Kaiserling, who had insomnia to sleep well. Bach asked one of his students-harpsichordist Johann Gottlieb Goldberg-to perform the variations for Count Kaiserling, and named the variations after Goldberg.

"I've tried to sleep while listening to the variations. They sure helped me fall asleep with the first several variations, but the tendency to fall asleep after hearing some variations such as variation 25, also known as The Black Pearl, drops drastically," Lang says. "It feels like scenes from the movie Inception."

After the hiatus, the pianist returned and was finally ready to record the Goldberg Variations.

He says he is grateful for the experience of not being able to perform onstage. As his 40th birthday approaches, he feels that it is the right time to perform the Goldberg Variations. He also calls the composer "the greatest", though he did not like Bach very much as a young boy.

In January, Lang and his wife, fellow musician Gina Alice Redlinger, shared the news of the arrival of their first child on social media.

The pianist says that becoming a husband and a father has enriched his life as a musician.

"I used to believe that life is a short-distance race and I have to make that dash with all my strength. But now, as I grow older, I think life is more of a marathon. A successful work-life balance depends on the ability to pace yourself," says the pianist. "I want to improve when I am 50 years old. And when I play Bach's Goldberg Variations at 50, it will be much better."

Lang is scheduled to perform in Europe and the United States this year, but the concerts may be postponed due to the COVID-19 pandemic.