As the nationwide college entrance exam, or gaokao, got underway on Wednesday with a record number of participants taking the test, businesses big and small seized the opportunity to cater to the needs of students and their families, and rake in profits.

Zeng Jin, who runs a bakery in Harbin, Heilongjiang province, is selling a special variety of mooncake to wish examinees luck. It features the Chinese characters "zhuangyuan". In ancient China, the characters referred to a candidate who finished at the top of the national-level recruitment exam for officials.

"I came up with this cake five years ago and named it 'zhuangyuan', and it is sold only during gaokao," she said, adding that some of her regular customers prodded her to start making the special mooncakes in early May.

Zeng said she sold more than 300 boxes of cakes for around 17,000 yuan ($2,389) in the two weeks leading to the gaokao. "My customers think it is the perfect gift to extend well wishes to an examinee."

The examination this year is the first since China optimized its COVID-19 response measures. A record 12.91 million examinees have signed up to participate in the gaokao this year, according to the Ministry of Education. It will last between two and four days, depending on the location.

For most Chinese students, the gaokao is a high-stakes exam that determines their academic futures and careers. The opportunity is used by businesses to promote their products and services, as there is a growing demand for things that can cushion the stress of preparing for the prestigious exam.

On online shopping platform Taobao, a number of stationery brands have launched gaokao kits, packaged in red and printed with blessings. Each kit, priced at around 15 yuan, has 13 items including pens, pencils, erasers and geometry tools. Data from the flagship store of a popular brand, M&G Stationery, on Taobao showed that it had sold more than 70,000 such kits over the past month.

Some parents and teachers are choosing to wear the qipao — traditional Chinese dress considered auspicious — or red clothes to cheer on the students taking the life-altering exam. In Mandarin, the character qi also refers to a flag, and a flag symbolizes victory, while the color red stands for courage and good luck.

"I spent 500 yuan to buy a red qipao a month ago in order to encourage my son during the gaokao," said Li Lei, the mother of a candidate, waiting outside an exam venue in Hegang, Heilongjiang, on Wednesday. "In fact, it is my first time wearing a qipao. I am hoping my son will score well and get admission to his dream college."

Zhang Sining, a researcher at the Liaoning Academy of Social Sciences, told Shenyang Daily the increase in demand is helping many businesses. "However, the students and their parents should treat consumption related to the exam rationally. They must avoid blindly following the trend and falling into the consumption trap."