Shunsuke was the only one who noticed the barista’s mistake.

It’s a five-minute walk from Kiyosumi Shirakawa Station in Koto Ward, on the third floor of Little Tokyo. Shunsuke’s mentor, barista Akira Nakadate, runs the cafe +Angle coffee works here, and Shunsuke brewed a special coffee for us.

The temperature of the water to be poured is 90 degrees. The water is carefully poured in four separate pours of 60 grams each. “The taste changes depending on the pouring time and amount of water,” says Shunsuke, who is thorough in his work and uses a precision measuring device and timer that can measure weight to the nearest 0.1 gram.

The beans he uses are from Yunnan, China, and he roasts them himself. In order to make the most of the beans’ natural appeal, he has studied over 30 different patterns, from how coarsely to grind the beans to the temperature of the water. “My dream for the future is of course to be a barista! I want to be able to properly explain the origins of coffee and the taste,” he says.

His mother, Mainami (39), who keeps a warm eye on her son, a second-grader at elementary school, said, “He loved trains all the time when he was in nursery school. He was the kind of kid who would memorize the names of stations on his own. But now he’s crazy about trains and coffee, and it’s about 20:8. As a parent, I want to let him do what he wants to do.”

Shunsuke first became obsessed with coffee two years ago. It all started with a honey latte he had at a cafe in Kiyosumi Shirakawa. He had the same latte at the same cafe about a month earlier. He thought it tasted good last time, but something felt different.

“It’s kind of bitter.”

Nakadate, a barista at the store, was surprised to hear this.

“Actually, we made a slight mistake in the roasting of the beans that day. We adjusted the extraction method in a creative way so the other customers didn’t notice, but Shunsuke was the only one who saw through it.”