A couple share a romantic moment on Friday outside a registry office in Beijing's Chaoyang district. Nov 11 this year was referred to as "Super Singles' Day". Wu Hailang / for China Daily

BEIJING - Couples looking to take advantage of the "most auspicious day in a century" flocked to sign their marriage certificates on Friday.

Roughly 4,000 couples tied the knot in the capital, a huge increase compared with the daily average of 450, show statistics from the Beijing Civil Affairs Bureau.

"We opened five more windows to help couples and put more workers on duty, but it was still far from enough to cope," said Li Lie, deputy director of Haidian district's registry office.

The onslaught of online reservations for marriage licenses started about a month ago, he said.

Nov 11 has been known as Singles' Day since the 1990s and is a time when many people say farewell to single life. This year was seen as extra special because it ends in 11.

Among the crowds at Haidian registry office was Zhang Ying and her husband.

"In Chinese, the date - 11/11/11 - represents 'forever' and 'devotion', so this is a once-in-a-lifetime chance," said Zhang. "We have been waiting for this day for a long time. The event is too unique to miss out."

Other cities also saw a rush, including Shanghai, where 5,007 couples had made it official as of 5 pm on Friday. The figure is about 20 times the daily average, according to the Shanghai Civil Affairs Bureau.

Meanwhile, the so-called Love Post Office, also in Beijing's Haidian district, gave away free gifts to couples to mark the auspicious occasion.

"We offered free postcards and 'Love Passports', which couples can get stamped every anniversary," said the manager, who gave only her last name, Liu.

She added that the post office, which offers a service to deliver love letters after seven years, based on the idea of the seven-year itch, will run special promotions every Nov 11 from now on.

Wu Ni contributed to this story.