Kindness cannot be quantified, and true kindness is not based on expectation of compensation. However, one young man's voluntary act of kindness toward a teenager is literally getting a 10,000 times payback. This inspiring story started 25 years ago in a small city in China.

Twenty-five years ago, Zhang Ai-Min was 24-years-old and frequently went to get his haircuts at a local hair salon in the city of Xuzhou in Zhejiang province of China. Sun Shen-Rong was a hair washer there. Sun was only 15 years old and his brother owned the hair salon, but Sun eventually decided to look for work in another city.

A few months later, Zhang went to Wenzhou on a business trip and ran into Sun. Sun talked about his unpleasant experience working at the hair salon. Zhang felt bad for him and said, 'Come to Xuzhou, I'll help you.' By that time, Sun's brother had already closed the salon and left Xuzhou, but Sun went to Xuzhou based on that one simple promise from Zhang.

Zhang kept his promise. He immediately helped Sun rent a place to start his own hair salon, and he also gave Sun 1,000 yuan. Zhang was only a clerk at the time earning a mere 90 yuan a month. The 1,000 yuan (about US$161) he gave him was equivalent to his wages for one year.

Sun worked hard at his hair salon. Zhang noticed that Sun was too busy to eat regularly, so he would buy meals for Sun. As Zhang later recalled, 'I was impressed by his hard work, and I treated him like a young brother to support him.'

Sun eventually closed the hair salon and went into the military and lost contact with Zhang. After he finished his military service, he went to Spain to seek opportunities. Sun labored in various service jobs such as waiting tables and street peddling, but he gradually started his own business. After years of hard work, he became a successful business leader in Spain.

Sun never forgot the person who helped him. Starting in 2008, he went back to China three times to try to find his benefactor. When he returned to Xuzhou, he neither could find Zhang, nor even find his hair salon's location in the growing and prosperous city. In 2010, he tried again but still failed. In 2012, he returned to Xuzhou for the third time. This time, he gave himself enough time there to look for Zhang's address, street by street and house by house, but he still failed.

Finally, he went to the police for help. He was given a list of over 140 Zhang Ai-Min. He called the one who seemed the right one but was told that person had moved long ago. Sun was finally ready to give up. The policeman decided to try his luck. He placed a call to one of the Zhangs on the list, and it happened to be the right one! Sun almost couldn't believe it but he recognized the voice from the other end of the phone. It's now been 25 years since they last met. When they saw each other, they hugged and cried. People who saw them all said it seemed like a scene out of an Asian drama.

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Now that Sun had succeeded in his business, he wanted to buy two houses to repay Zhang's kindness from 25 years ago. Zhang immediately declined the gift. He had retired early and started a small business with a friend. He said it was enough to live on.

Sun still wanted to show his gratitude in a substantive way. Because he is a successful merchant in Spain, he came up with an idea to start a business in Xuzhou to sell items such as wine and olive oil. He would invest 10,000,000 yuan (or US$1.6 million) and Zhang would be the chief executive to run the business with full authority. To Sun, it was a way to continue the friendship and the bond he had with Zhang.

Although Sun was not motivated by profit to open the wine business, it's been doing well for the past 2 years. Sun now visits Xuzhou frequently and the two men's families have gotten together for Spring Festival and Autumn Festival celebrations.Their bond is based on trust and they treat each other like real brothers. Zhang is 51 and Sun is 42 now. Once, Zhang hurt his back and couldn't get out of bed, Sun would carry him to the bathroom. Sun said this about Zhang: 'We met by pure chance and never sought to make money from each other. He is my big brother for life."