Ever since, they've returned to Europe almost every year and gradually feel at home there. "We still admire the famous halls and audiences, but we are at ease. And we bring Chinese works and introduce our own composers."
Commissioned by Beijing Symphony Orchestra, Guo created The Rite of Mountains in memory of the horrific earthquake in Sichuan in May 2008. The haunting elements and traditional Chinese percussion, often used in folk operas, are featured in the composition, which references Stravinsky's Rite of Spring.
"You may hear the earthquake, people's tears but also the restoring power of nature," Tan says. "Guo enables percussionist Li Biao to deliver a very spectacular presentation of his craft. Most importantly it is very Chinese, a great representative of China's contemporary music."
Dedicated to London's Olympic Games, Guo's Lotus opens with one violinist playing solo and then more violinists joining in one after another, symbolizing the petals of the lotus flower as it opens. It also features non-Western musical scales, including those from China and Southeast Asia.
"When Tan asked me to write a piece for their concert in London, I first considered using cultural symbols from the host country. In the end, I decided to compose a work that is more lyrical and Oriental," Guo says. "In numerous Chinese poems, songs and essays, the lotus is a symbol of friendship, as well as a messenger."
"I love the fact that Lotus is not a purely traditional Chinese piece but is written in a modern style with a Chinese flavor. It's a beautiful marriage between Western and Eastern music," comments Pieter Schoeman, concertmaster of London Philharmonic Orchestra, who played the piece together with Beijing Symphony Orchestra in London.
The busy summer is just one part of the busiest year in the orchestra's 35-year history, in which they will play 100 concerts, and invite foreign musicians such as conductor Christoph Eschenbach, pianists Lang Lang, Jean-Yves Thibaudet and Tzimon Barto, violinists Vadim Repin and Michael Barrenboim.
China now has 58 symphony orchestras, the world's largest number of symphony orchestras, after the United States and Germany, according to the Association of Chinese Symphony Orchestras.
And since performances are related to financial support, it is clear that the Beijing Symphony Orchestra is receiving a lot of support this year.
Tan started its ambitious 2012 season on Feb 8 and announced the municipal government would give the orchestra 50 million yuan ($7.85 million) this year.
He says the municipal Party chief Liu Qi was shocked when he visited the orchestra's shabby rehearsal room, which they have rented from Beijing Song and Dance Company for years, at Shuangjing, East Third Ring Road, in July 2011. Liu promised to help the orchestra to hire world-class musicians and build their own hall.
Interestingly, the view in the classical music world is that an orchestra's season runs from September to May, but Beijing Symphony Orchestra began in February, because the municipal government decides its annual financial budget at this time every year.
Tan says the finance bureau and culture bureau have their rules. For example, the round trip flight for a foreign expert (such as a musician) can be no more than 15,000 yuan ($2,375). One day of expenses - including hotel, meals and transportation for a musician - should be no more than 600 yuan.
Tan says he had no idea when the "ridiculous" rule was formed, but anyway, he got only 570,000 yuan from the government before they set off for London in July.
He was "nervous" again, not on the podium but wondering how to deal with the contracts of big names. He knows Eschenbach loves the southern room of the Raffles Beijing Hotel, in which they can open the window to look down on the stream of cars on Chang'an Avenue.
Tan had to visit the cultural and finance bureaus several times and even wrote to Beijing Vice-Mayor Lu Wei, who is in charge of publicity.
After the London Olympic Games, he got more money (though he won't say how much) and enough to complete this year's engagements.
Tan was appointed head of the orchestra in 1992 and it did not turn professional, even when he started to reform the orchestra in 1998.
He did start auditions. Every musician played behind a curtain to a jury composed of musicians from outside the company. Less than 20 of 50 passed the audition. Tan gave some old members a second chance and others had to change position or take on management and marketing.
He got threatening calls. He received calls from friends who tried to persuade him to keep someone in the orchestra. He got an official's "order" to give somebody a seat in the orchestra.
"It's not difficult to start something new, but it is really challenging to break something old," Tan recalls.
Now the 96-member orchestra has eight international musicians, recruited from Germany, France, Italy, Switzerland and Russia.
A lot of Chinese artists and ensembles performed in London during the Olympics, but only Beijing Symphony Orchestra's concert sold tickets. According to Southbank Center's performance sales analysis, 2,163 seats, among 2,546 were sold, and 65 were retained by the presenter.
Though more Chinese performance companies tour abroad, most are government cultural exchange projects, and do not really sell tickets, but instead perform for organized audiences that are mostly Chinese.
Tan has three rules: selling tickets through established European agencies; performing to mainstream Western audiences; and performing both Western and Chinese works.
"It's very helpful for an orchestra's growth to collaborate with renowned musicians and to tour places where people really appreciate music. Good musicians and audiences broaden our vision," Tan says.
The orchestra's next destination will be the United States, in 2013.