Purple underwear was apparently a particularly popular fashion trend for this year’s gaokao in northeastern China as test-tasters dressed for success on the annual college entrance exam.

In the local dialect, when the word for “purple” and “butt” combine, they sound similar to a phrase meaning “totally sure.” Hoping to go in with that kind of certainty to the exam, many students prepared by putting on their best pair of purple undies.

A Taobao seller surnamed Wang told reporters that sales for purple underpants at his online shop had really picked up since May with a few hundred pairs being bought up. Meanwhile, the same colored underwear sold out at other online outlets.

Of course, there’s nothing saying that this technique should only apply to the gaokao. Perhaps the secret to achieving fame and fortune is simply to wear purple underwear each and every day.