A funeral for Sakamoto, who died last Tuesday, was already held with only close relatives in attendance, the office said. The exact cause of death was not immediately known. With his interest in environmental and peace issues, Sakamoto had been actively involved in the anti-nuclear power movement in recent years in the wake of the 2011 Fukushima nuclear disaster triggered by a killer earthquake and tsunami. [...] The musician also led More Trees, a Tokyo-based forest conservation group established in 2007. Sakamoto, who began spending most of his time in New York in the early 1990s, went public with his throat cancer diagnosis in 2014 and his rectal cancer diagnosis in 2021. Cancer later spread to his lungs, requiring him to undergo surgeries in October and December 2021. Sakamoto discussed in detail his cancer diagnosis and how he had been coping with it in an article titled "Living with Cancer," published by the literary magazine "Shincho" in June 2022.