Chinese customs officers get a lesson in perfecting their smile, by holding chopsticks between their teeth.

Women of true beauty do not reveal their teeth when they are smiling, according to a traditional Chinese adage.

Not anymore, one government bureau has decided. 

During a "How to Smile" course organized by the Dalian Port Inspection Station in China’s northeastern province of Liaoning, customs officers were given the strange assignment of holding a chopstick between their teeth as they grinned. 

"The purpose is to perfect their smiles," Zhang Tianbao told NBC News. Zhang, the political officer in charge of the Dalian station, said that seeing one’s pearly whites was imperative to a beautiful smile.

 "The best result is that they can show eight teeth while they are smiling," he said.

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This is not the first time China has gone academic on what constitutes a good smile. Yang Jinbo, the etiquette adviser for the 2008 Beijing Olympics, explained how the transition was made. 

"China is part of the international world, we change our traditional culture so that the international world will understand that we’re friendly."

NBC News' Yanzhou Liu contributed to this report.

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