A rookie in giving red envelope money, Luo is not only worried about saving money, but also how much to give and to whom.

"I thought it would be easy, but it is much more complicated. My mom told me to give my second niece more because she is going to primary school this year. My uncle gave me quite a bunch of red envelope money when I entered college," says Luo, who is amazed by her mother's memory and shrewd calculation. Chinese-American student Emily Wu, 26, confronts a similar situation. Growing up in America since she was five years old, Wu feels these considerations are strange and make her feel uncomfortable.

Wu returned two weeks ago with her mother for the winter vacation. She received a red envelope while visiting her grandfather's brother, whom she had only met three times before. Wu was stunned when she saw 1,000 yuan (US$146) in the envelope after she got home.

She told her mom about the large amount and wanted to return the money. But her mother stopped her, saying it would be impolite and unlucky since it's the yasui qian. Nobody returns yasui qian.

Wu's mother consoled her with a great idea in the money-go-round: She would give a big red envelope to the old man's daughter on her wedding next month.

"That way, the renqing (reciprocal social relations) is clear," says Wu. "I know how renqing works and I agree that it's reasonable to buy gifts to those friends who got me presents before. But I didn't realize it was such a strict custom here. With no written rules, it seems like common sense to everyone."

There is no written rule about renqing. You don't find it in textbooks or from teachers. It's more like a practical skill you pick up from your parents, friends and colleagues - nothing formal. But those who don't follow the exacting etiquette of giving are considered impolite and immature.

Ren usually means person and refers to a person's social skills in this context. Qing means relations. Renqing means the customs that guarantee good social relations.

There are some commonly known renqing, such as giving yasui qian in red envelopes on Chinese New Year, giving red envelopes at births, weddings, giving birthday gifts, entry to college gifts, and so on - there are many occasions. In a word, it's a way of equal trading. Babies get money that mom and dad put in the bank or spend in what they consider the child's best interest.

For example, Luo remembers that her mom would count the money in each envelope before giving her all the yasui qian.

"It's just an exchange. My uncle gives me red envelope money, and my mom also gives it to his daughter," says Luo.

Luo's mom gets upset at times. If she finds out that she has given a relative less than what her daughter has received, she'll make a note to give more to that person's child next year. If it's the other way around, Luo still remembers how her mom would say "stingy."

"But most envelopes are about the same as what my mom gives because everyone knows about the standard price," says Luo.

It's the same for a wedding, another big time to cash in or pay out with envelopes. Guests always write their names on the red envelopes. The newlyweds register all their income from everyone and return it in a few years - when their wedding guests get married, or on another appropriate occasion.

Some new couples don't even open the gift envelopes of money - they keep it until the day the giver gets married. They change an envelope, write their name and give it back.

In daily life, we apply the idea of renqing without thinking about it.

"It's second nature for most people," says Chen Fei, 29, an account manager. "If you treat me for a dinner tonight, I'll take you to karaoke next time. If I brought cosmetics for you from Hong Kong, you might bring me chocolates from Belgium later on.

"Nobody can escape it unless you live alone on a mountain, grow your own crops and make your own food for your whole life," says Chen.