Saturday in Akihabara, humanoid robots fight full contact in an octagon while their pilots stand ringside. REK, the American robot-combat outfit, comes to Japan for a single day, staged by Robostadion. The exhibition floor opens free from 10am; the ticketed bouts start at 3pm and finish around six. Standing room is 3,000 yen, general seating 5,000, premium 10,000, and ringside 20,000. Part spectacle, part a plain look at where the machines have got to.