Seoul, South Korea • In 1950, when Han Sung-joo was 10, shrapnel from an artillery shell lodged in his hip. This happened as Gen. Douglas MacArthur’s troops, fresh from the bold Incheon landing, were retaking this city — it would be lost and retaken again — after North Korea’s June invasion. The shell fragment was still there when Han served as his nation’s minister of foreign affairs (1993-1994) and as ambassador to the United States (2003-2005). He lives today with this metallic reminder of the fact that his nation lives in a dangerous neighborhood. His brother-in-law died when North Koreans killed 17 South Korean officials in a 1983 attempt to assassinate South Korea’s president during a visit to Burma.