While working at a venture IT company, Tetsu Kasuya developed type 1 diabetes. It was then that he discovered the wonders of coffee. In 2013, he became a barista at the coffee shop Coffee Factory, and in 2016, he became the first Asian to win the world championship World Brewers Cup. In addition to running the coffee company Philocoffea, he is also involved in a wide range of activities, including product development and product promotion for Family Mart and Nestlé Japan, and training top baristas around the world, all while maintaining the YouTube channel TETSU KASUYA World Brewers.