Official campaigning began Thursday for Japan's House of Councillors election, with Prime Minister Shinzo Abe seeking to maintain political stability to press ahead with the first-ever constitutional revision and a planned consumption tax hike.The July 21 poll comes amid heated debates between ruling and opposition parties over a controversial estimate on required levels of retirement savings that sparked concerns about the pension system's ability to provide for people in rapidly aging Japan.The October tax hike -- from 8 percent to 10 percent -- that is likely to hit household spending, i…READ FULL ARTICLE