BINZHOU, China (KOREA HERALD/ASIA NEWS NETWORK) - A restaurant in Binzhou, China, came up with a perky idea to give discounts to customers who can squeeze through narrow metal bars.

"People are always thinking about a big meal when they enter a restaurant. If they fail to squeeze through the frame they might think, maybe we are overweight, maybe we should control the amount of food we order," said Mr Zhao Lang, the owner of the restaurant, in an interview.

Visitors who make it through the narrowest gap, which is 15cm wide, get free beer for their table and a free meal.

Others who can squeeze through a gap of 18cm gets five beers on the house. Passing through 25cm gap gets one a single free beer.

If the challenge is too daunting, there's a more comfortable entrance of an opening of 30cm width, but those who pass through here do not get any reward, as this is considered to be a "normal fit".

Mr Zhao said that he came up with the idea to play a game with the customers in April, when flower pollen forced the restaurant to keep the front door half-shut.

"In April there always are catkins in the air, so we usually keep only half of the doorframe open," he said, "Some fat guys had to really try to get through. That's when we thought it would be fun to create a game that measures body sizes and combine some discounts and special offers with it."

The idea is proving to be a boon to the restaurant's business, as people have started to share on social media how they fared with the bars, instantly turning it into a catchy online marketing scheme.