[1/5] U.S. President Joe Biden and Japan's Prime Minister Fumio Kishida attend a bilateral meeting ahead of the G7 leaders' summit in Hiroshima, Japan, May 18, 2023. Kiyoshi Ota/Pool via REUTERS HIROSHIMA, Japan, May 19 (Reuters) - Leaders of the world's advanced democracies start their Group of Seven (G7) summit on Friday in Hiroshima with a sombre remembrance of the costs of war as they grapple with the conflict in Ukraine. Ahead of a summit focused heavily on ending Russia's war in Ukraine and on preventing conflict with China, Japanese Prime Minister Fumio Kishida will gather world leaders at a...