Opened last month, Pump is the newest addition to Tokyo's continuously expanding craft-beer scene. The interior is clean and simplistic with unadorned concrete walls, spotless counters and tables and a stainless-steel wall behind the bar counter.

"A few customers are a bit intimidated by how clean and plain the place is," says owner Yasuhiro Ijima, a former salaryman who quit his engineering job at an IT company last year to focus on starting his own business. "So we're making the place a bit more interesting by adding colorful posters on the wall."

Indeed, Pump, while clean and still filled with the scent of freshly cut wood from the new tables placed around the interior, does come off as dreary and prison-like with its concrete wall. This simplicity even extends to the menu. While other bars offer a wide range of choice when it comes to drinks and food, Pump's menu fills both sides of one sheet of paper — with very large letters. Ijima only serves 10 beers at a time.