Well into their 40s, this "boy band" continues to be a mainstay of the entertainment landscape in Japan Rumours are rife in Japan that one of the country's most well-known and long-lived pop groups, SMAP, might be on the verge of a break up. Their talent agency has said only that they are in negotiations over their future, but as the BBC's Mariko Oi explains, a split would be a huge shock for Japa