The shift in the rugby world’s axis was apparent in a suburban Tokyo park last weekend. There was nothing unusual about the dozen schoolboys letting off steam in the late afternoon sunshine. But for the first time any of their parents could remember, they had abandoned their regular kickabout to experiment with a squeaky clean oval ball. Rugby mania is also seeping into offices and bars, sparking conversations among people who Japanese sporting convention dictates should be chewing over the recent climax to the professional baseball season. But these are not ordinary times. Japan’s heroics at the Rugby World Cup – where they reached the quarter-finals before being beaten by South Africa – have helped to cultivate a new breed of rugby devotees, including this writer’s normally taciturn barber, who unbidden, brandished his clippers and offered an analysis of the Brave Blossoms’ decisive pool victory over Scotland – only the third rugby match he had ever watched. More than 54 million people in Japan followed that game on TV – almost half the population and a record for any rugby match. And so the superlatives go on: more than a million people crammed into fanzones and a quarter of a…