HIROSHIMA: Since the age of seven, Japanese schoolboy Shun Sasaki has been offering free guided tours to foreign visitors of the Hiroshima Peace Memorial Park with a mission: ensuring that the horrors of nuclear war do not fade from memory with the passage of time. Aged 12 now, Shun has conveyed that message to some 2,000 visitors, recounting in his imperfect but confident English the experiences of his great-grandmother, a ‘hibakusha’ who survived the atomic bomb.