SADO, Japan (AP) — Japanese officials on Sunday paid tribute to workers at the country's Sado Island Gold Mines but offered no apology over Japan’s brutal wartime use of Korean forced laborers , highlighting lingering tensions between the neighbors over the issue. South Korea a day earlier announced that it was boycotting the memorial , saying it had been impossible to settle unspecified disagreements between both governments in time for the event. The Korean absence is a major setback in the