Hiroshima Castle ' , sometimes called ' was a castle in Hiroshima , Japan which was the home of the " daimyō " ( feudal lord ) of the Hiroshima han ( fief ) . The castle was constructed in the 1590s , but was briefly destroyed by the atomic bombing on 6 August 1945 . It was rebuilt in 1958 , a replica of the original which now serves as a museum of Hiroshima ' s history prior to World War II . History . Mōri Terumoto , one of Toyotomi Hideyoshi ' s council of Five Elders , established Hiroshima castle in 1589 at the delta of the Otagawa river . There was no Hiroshima city or town at the time , and the area was called Gokamura , meaning ' five villages . ' Beginning in 1591 , Mōri governed nine provinces from this castle , including much of what is now Shimane , Yamaguchi , Tottori , Okayama and Hiroshima Prefecture s . When construction on the castle began , Gokamura was renamed Hiroshima , as a more impressive name was called for . " Hiro " was taken from Ōe no Hiromoto , an ancestor of the Mōri family , and " Shima " was taken from Fukushima Motonaga who helped Mōri Terumoto choose the castle site . Some accounts state that the name ' Hiroshima ' , meaning literally ' wide island ' , comes from the existence of several large islands in the delta of the Otagawa , near the castle ' s site . Following the battle of Sekigahara in 1600 , Mōri was forced out of the castle , retreating to Hagi in today ' s Yamaguchi prefecture . Fukushima Masanori became the lord of Aki and Bingo province s ( which today comprise Hiroshima prefecture , and of Hiroshima castle ) . However , the new Tokugawa shogunate forbade any castle construction without permission from Edo ; this was part of how the shogunate kept the " daimyō " from gaining power and overthrowing the shogunate . When Fukushima repaired the castle following a flood in 1619 , he was dispatched to Kawanakajima in today ' s Nagano prefecture . Asano Nagaakira became lord of the castle . From 1619 until the abolition of the feudal system during the Meiji Restoration ( 1869 ) , the Asano family were lords of Aki and Bingo province s . After the Meiji Restoration , the castle came to serve as a military facility , and the Imperial General Headquarters was based there during the First Sino - Japanese War in 1894 - 1895 . The foundations of several of the GHQ outbuildings , just a few hundred paces from the castle ' s main tower , remain today . The castle was destroyed in the atomic bomb blast of August 6 , 1945 . For many years , it was believed the castle structure was blown away by the explosion that destroyed Hiroshima , but newly discovered evidence suggests the explosion only destroyed the lower pillars of the castle , and the rest of it collapsed as a result . The present tower , constructed largely of concrete , was completed in 1958 . " Daimyō " of Hiroshima . < nowiki > * < / nowiki > " The years listed are those in which the lord occupied Hiroshima castle , not the years of his life . " < nowiki > * * < / nowiki > " All of the lords after Asano Nagaakira enjoyed the same 426 , 500 " koku " . Structure . The castle was originally constructed in wood , pine primarily , and had attached wings to the east and to the south . It was completed sometime between 1592 and 1599 , and was designated a National Treasure in 1931 . The reconstructed castle features the main tower ( " tenshu " ) only , which is made primarily of reinforced concrete . Its five floors stand 26 . 6 meters above the stone foundation which , in turn , is 12 . 4 meters high off the ground . However , in 1994 , a gate and a " yagura " in the " ninomaru " were re - constructed out of wood using the original methods . An excellent example of a " hirajiro " or flatlands ( plains ) castle , Hiroshima castle once had three concentric moats in addition to the Otagawa river to the west ( now called the Hongawa ) , which provided an additional natural barrier . The two outer moats were filled in during the late 19th & early 20th centuries , and much of what was once within the castle grounds is now modern urban areas , including homes , schools , offices and shops . A number of secondary castle buildings , towers and turrets once stood , and a Shinto shrine called Hiroshima Gokoku Jinja is located within the innermost moat , having been moved there after 1945 . Within the castle walls , three trees survived the atomic bombing , a eucalyptus and a willow at approximately 740m from the hypocenter , and a holly approximately 910m from the hypocenter . Both specimens are preserved just beyond the Honmaru . Also located inside the Honmaru is the concrete bunker from which the first radio broadcast out of Hiroshima following the atomic bombing was made .