In this special edition, the results of Japanese national project on development of superconducting generators (SCGs) are reported. Before the reports, the history of developing conventional generators, (that is, larger generator requests higher technology of cooling) motivation of developing SCGs (which is on way of higher cooling technology for larger generator), key technologies of SCGs except superconducting technology, features of SCGs, (that is, larger capacity, small size, high efficiency, good characteristics for power system operation) and so on, present situation of the development and some comments of real application are described.