Special issue on the Great East Japan Earthquake and the activities of members and alumni of the School of Medicine, Keio University.

The magnitude-9.0 Great East Japan Earthquake, which struck at 14:46 JST on March 11, 2011, was the largest ever recorded in Japan. Strong quakes were felt not only in Tohoku, the closest region to the epicenter, but also nationwide from Hokkaido to Kyushu. This exceptional event was followed by huge tsunami waves that severely damaged the Fukushima Daiichi nuclear power plant, which consequently developed into an unprecedented crisis. A huge amount of infrastructure and innumerable buildings were damaged in more than 17 prefectures, over 19,000 people died or went missing in 12 prefectures, and more than 5000 people were injured in 20 prefectures.1 Successive failures or shutdowns of nuclear and non-nuclear power plants brought a sustained shortage of electricity across a wide area of Japan, a situation that seriously affected our university and hospital as well as our daily lives and living environment. In response to the crisis, in addition to national and local governmental initiatives, numerous voluntary organizations, companies, schools, and individuals from all over Japan and worldwide headed toward the disaster-stricken area to help rescue victims, deliver subsistence goods, remove rubble, and restore infrastructure. Thanks to the strenuous activities of the Japan Self-Defense Forces, United States (U.S.) Forces, and devoted civilians, major items of infrastructure, including highways, shinkansen (bullet train) tracks, airports, and harbors were restored quite quickly. The damaged nuclear plants were finally stabilized with the best possible efforts, although it will likely be more than three decades before they are finally decommissioned.2