Vending machine operators have recently been seeking new ways to expand their sales as they face competition from convenience stores that offer an increasing variety of products.

Japan has a staggeringly high density of vending machines — about 4.9 million units nationwide. About half of these units sell beverages, with annual sales standing at nearly ¥5 trillion at the end of 2016, according to the Japan Vending Machine Manufacturers Association.

But the spread of convenience stores throughout the country is posing a threat, prompting vending machine operators to find unique or unconventional ways to expand their functions.