Tens of thousands of Chinese couples are rushing to tie the knot on Sunday in the belief that the "lucky number day" will bring them a perfect marriage.

When written out numerically, Sunday is the 10th day of the 10th month of 2010.

With the number 10 implying perfection in Chinese, the 10/10/10 lucky day has been selected by a lot of young people as the day to exchange their vows, just as the days in previous years - 08/08/08 and 09/09/09 - which were also days believed to be lucky.

"I tried to book a fancy hotel in March, more than six months ahead, but I found that all the good wedding banquets on Oct 10 were already sold out," said Liu Mengmeng, 29, from Shanghai.

Similarly, tables for wedding parties in most hotels in China's major cities were hard to book even half a year ago.

"We charge 3,588 yuan ($538) for each table, which is 20 percent higher on Oct 10 than usual days. In spite of that, the banquet halls had been fully booked in April," said Ma Chuan, marketing manager of the Chang An Grand Hotel in Beijing.

Ma said more people might choose Oct 10 as their big day since it falls on the weekend.

"This Oct 10 happens to be a Sunday. Sept 9, 2009 and Aug 8, 2008 fell on working days, and many guests might not have shown up at the wedding if you had chosen those two days," Ma said.

In Shanghai, the usual booking schedule was as long as 12 months in advance, according to a marketing manager surnamed Zhu with the Hongqiao Villa hotel.

"There are usually several lucky days in a year, and you have to book a year in advance for them," Zhu said.

She said the next lucky day after Oct 10 will be Oct 23 - and for that day the entire wedding hall has been booked.

In Shenzhen, wedding service agent Yang Yi said he had arranged six couples' weddings for Oct 10, and is preparing more.

"Some couples came to me so late that I couldn't get everything ready in time, so they had to put off their plans," Yang said. "After all, everybody wants to marry on that day, and the earlier you start, the better wedding you get."

Wedding services for Oct 10 were booked before August in Beijing, and the schedule should be set by September at the latest in Shenzhen, Guangdong province.

Marriage register offices in most cities were similarly crowded, as civil affairs bureaus in many cities such as Beijing, Shanghai, Shenzhen, Hangzhou, Jinan, Dalian and Zhengzhou decided to work extra hours on Sunday to register new couples.

According to earlier reports in the Shanghai Morning Post, the local authority was expecting record-setting registration volume on Sunday. The city had 7,189 marriage registrations on Aug 8, 2008 and 8,852 on Sept 9, 2009.

"Nearly 700 couples had come to the registration office for reservations," said an official with the marriage register office in the Dongcheng district in Beijing who refused to give his name.

He said that since early September people have been able to register at the office in person to place an order for marriage registration on Oct 10, and no one would be able to register that day without a reservation.

"That number of 700 is almost tenfold the everyday registration number, so we have arranged extra staff to ensure all the couples can get registered on that day," he said.