Sumiko Iwamuro knows a thing or two about juggling work.She spends her days behind the counter at a family-run specialty "gyoza" dumpling restaurant and nights once or twice a month moonlighting under her stage name DJ Sumirock. It is an impressive feat for someone 82 years old, although she insists otherwise.At 2 a.m. when other octogenarians are fast asleep, Iwamuro -- donning her trademark sunglasses and bright red lipstick -- is spinning beats to the delight of the crowd at a dance club in Kabukicho, the famous red-light area in Tokyo's Shinjuku district."As long as you are not causing …READ FULL ARTICLE