Tori Yaro, a small pub in Shibuya, one of Tokyo’s busiest nightlife districts, is trying a new way to control its atmosphere. On its front door, a large sign calls the bar an "izakaya for younger generations" and clearly states that only customers aged 29 to 39 may enter.

The rule isn’t completely strict, though. The sign explains that older customers can enter if they come with someone aged 39 or younger, and staff members' family and business partners are also welcome. These exceptions, however, are written in very small print, so many people only notice the main warning.

Why the age limit? Toshihiro Nagano, a company representative, says the reason is simple. "Essentially, our customer base is young", he explains, adding that the pub is noisy, casual, and quite inexpensive. Younger guests enjoy the lively mood, but older customers sometimes complain about the noise.

By setting an age restriction, the pub hopes that everyone will feel comfortable and satisfied.

Tori Yaro isn’t the only restaurant with age rules. Another nearby izakaya has the opposite idea. Yaoya Ba, a slightly fancier restaurant, mainly welcomes people aged 25 and up, though under-25s can dine if they’re in the company of an older customer.

"We want to be a place where adult customers can relax and enjoy their meals," says owner Masayuki Segawa.

Japanese online reactions have been divided. Some people say restaurants should be free to choose their style and target customers, while others feel that age limits are unfair and even discriminatory.

For now, Tori Yaro says the rule is flexible and may change in the future. If customers understand that the pub is loud and energetic, staff may still let them in.

The goal, they say, isn’t to exclude people, but to create a space where customers leave smiling.