Which country unveiled the Izumo, the largest warship since World War II?

Japan
Izumo is the largest warship of Japan. It is the largest warship unveiled by Japan since World War II. The Izumo has a crew of 470, and with a standard displacement of 19,500 tones (27,000 tonnes at full load), it is as large as the storied Yamato-class battleships which fought U.S. Naval forces in the Pacific theater of World War II.