With students about to sit in test rooms for the all-important national college entrance examination, or gaokao, on Friday, parents and teachers have been racking their brains to give them emotional support.

Zongzi, a festive food for Monday's Dragon Boat Festival, has emerged as a star on the list of good-wish items.

This year's gaokao starts on Friday and will take two to four days depending on the location. The scores will largely determine candidates' destinies in higher education — whether they can go to college, and what level of college they will be eligible for.

As the flipping of pages of study materials comes to an end, teachers and parents have shifted their attention to easing candidates' nerves and wishing them good luck. Many have chosen to do so by using something that can be interpreted as having auspicious meanings.

Primarily made with glutinous rice and often wrapped in bamboo leaves, triangular zongzi are a festive food for the Dragon Boat Festival.

Because the start of the exam and the festival are close together this year, the festive food has been turned into an edible talisman for good grades.

In Wuhan, Hubei province, students at Wuhan No 23 Senior High School who are about to take the test went into the canteen on Tuesday by entering through a door decorated with strings of zongzi, as school leaders waited to give them a pep talk. Many students also leaped to hit the food with their heads, Wuhan-based Jimu News reported.

The little ritual represents the Chinese word gaozhong, or "achieving high grades", as students jump "high", while zongzi serves as a pun for zhong, or "right on target".

"Through such creative activities, we hope to enhance their confidence so that they can have a more positive mindset for the exams," an unnamed school official told Jimu News.

Zongzi merchants have also taken advantage of the pun to boost their sales. They have rolled out special packaging that wishes test-takers good luck, along with handwritten gift cards, with hundreds of products sold on the Tmall e-commerce platform.

In addition to online promotions, at one supermarket in Fuzhou, Fujian province, a zongzi gift package even included a picture depicting someone ranking first in a top-level exam.