Hiroshima Hiroshima gained city status on April 1 , 1889 . On April 1 , 1980 , Hiroshima became a designated city . Kazumi Matsui has been the city ' s mayor since April 2011 . History of Hiroshima . Sengoku period ( 1589 – 1871 ) . Hiroshima was founded on the river delta coastline of the Seto Inland Sea in 1589 by the powerful warlord Mōri Terumoto , who made it his capital after leaving Koriyama Castle in Aki Province . Hiroshima Castle was quickly built , and in 1593 Terumoto moved in . Terumoto was on the losing side at the Battle of Sekigahara . The winner , Tokugawa Ieyasu , deprived Mori Terumoto of most of his fiefs including Hiroshima and gave Aki Province to Masanori Fukushima , a daimyo who had supported Tokugawa . Imperial period ( 1871 – 1939 ) . After the han was abolished in 1871 , the city became the capital of Hiroshima Prefecture . Hiroshima became a major urban center during the imperial period as the Japanese economy shifted from primarily rural to urban industries . During the 1870s , one of the seven government - sponsored English language schools was established in Hiroshima . Ujina Harbor was constructed through the efforts of Hiroshima Governor Sadaaki Senda in the 1880s , allowing Hiroshima to become an important port city . The Sanyo Railway was extended to Hiroshima in 1894 , and a rail line from the main station to the harbor was constructed for military transportation during the First Sino - Japanese War . During that war , the Japanese government moved temporarily to Hiroshima , and Emperor Meiji maintained his headquarters at Hiroshima Castle from September 15 , 1894 to April 27 , 1895 . The significance of Hiroshima for the Japanese government can be discerned from the fact that the first round of talks between Chinese and Japanese representatives to end the Sino - Japanese War was held in Hiroshima from February 1 to February 4 , 1895 . New industrial plants , including cotton mills , were established in Hiroshima in the late 19th century . Further industrialization in Hiroshima was stimulated during the Russo - Japanese War in 1904 , which required development and production of military supplies . The Hiroshima Prefectural Commercial Exhibition Hall was constructed in 1915 as a center for trade and exhibition of new products . Later , its name was changed to Hiroshima Prefectural Product Exhibition Hall , and again to Hiroshima Prefectural Industrial Promotion Hall . During World War I , Hiroshima became a focal point of military activity , as the Japanese government entered the war on the Allied side . About 500 German prisoners of war were held in Ninoshima Island in Hiroshima Bay . The growth of Hiroshima as a city continued after the First World War , as the city now attracted the attention of the Catholic Church , and on May 4 , 1923 , an Apostolic Vicar was appointed for that city . World War II and atomic bombing ( 1939 – 1945 ) . During World War II , the 2nd General Army and Chugoku Regional Army were headquartered in Hiroshima , and the Army Marine Headquarters was located at Ujina port . The city also had large depots of military supplies , and was a key center for shipping . The bombing of Tokyo and other cities in Japan during World War II caused widespread destruction and hundreds of thousands of deaths . For example , Toyama , an urban area of 128 , 000 , was nearly fully destroyed , and incendiary attacks on Tokyo claimed the lives of 100 , 000 people . There were no such air raids in Hiroshima . However , the threat was certainly there and to protect against potential firebombings in Hiroshima , students ( between 11 – 14 years ) were mobilized to demolish houses and create firebreak s . On Monday , August 6 , 1945 , at 8 : 15 a . m . , the Atomic Bomb " Little Boy " was dropped on Hiroshima by an American B - 29 bomber , the " Enola Gay " , flown by Paul Tibbets , directly killing an estimated 80 , 000 people . By the end of the year , injury and radiation brought total casualties to 90 , 000 – 140 , 000 . The population before the bombing was around 340 , 000 to 350 , 000 . Approximately 69 % of the city ' s buildings were completely destroyed , and another 7 % severely damaged . The public release of film footage of the city post attack , and some of the Atomic Bomb Casualty Commission research , about the human effects of the attack , was restricted during the occupation of Japan , and much of this information was censored until the signing of the San Francisco Peace Treaty in 1951 , restoring control to the Japanese . However , worldwide , only the most sensitive , and detailed weapons effects information was censored following the bombing . There was no censorship of accounts written by survivors ( " Hibakusha " ) . For example , the book " Hiroshima " written by Pulitzer Prize winner John Hersey , was originally featured in article form and published in the popular magazine " The New Yorker " , on 31 August 1946 . It is reported to have reached Tokyo , in English , at least by January 1947 and the translated version was released in Japan in 1949 . Despite the fact that the article was planned to be published over four issues , " Hiroshima " made up the entire contents of one issue of the magazine . " Hiroshima " narrates the stories of six bomb survivors immediately prior and for months after the dropping of the Little Boy bomb . The oleander is the official flower of the city of Hiroshima because it was the first to bloom again after the explosion of the atomic bomb in 1945 . Postwar period ( 1945 – present ) . On September 17 , 1945 , Hiroshima was struck by the Makurazaki Typhoon ( Typhoon Ida ) . Hiroshima prefecture suffered more than 3 , 000 deaths and injuries , about half the national total . More than half the bridges in the city were destroyed , along with heavy damage to roads and railroads , further devastating the city . Hiroshima was rebuilt after the war , with help from the national government through the Hiroshima Peace Memorial City Construction Law passed in 1949 . It provided financial assistance for reconstruction , along with land donated that was previously owned by the national government and used for military purposes . In 1949 , a design was selected for the Hiroshima Peace Memorial Park . Hiroshima Prefectural Industrial Promotion Hall , the closest surviving building to the location of the bomb ' s detonation , was designated the Genbaku Dome ( 原爆ドーム ) or " Atomic Dome " , a part of the Hiroshima Peace Memorial Park . The Hiroshima Peace Memorial Museum was opened in 1955 in the Peace Park . Hiroshima was proclaimed a City of Peace by the Japanese parliament in 1949 , at the initiative of its mayor , Shinzo Hamai ( 1905 – 1968 ) . As a result , the city of Hiroshima received more international attention as a desirable location for holding international conferences on peace as well as social issues . As part of that effort , the Hiroshima Interpreters ' and Guide ' s Association ( HIGA ) was established in 1992 in order to facilitate interpretation for conferences , and the Hiroshima Peace Institute was established in 1998 within the Hiroshima University . The city government continues to advocate the abolition of all nuclear weapon s and the Mayor of Hiroshima is the president of Mayors for Peace , an international mayoral organization mobilizing cities and citizens worldwide to abolish and eliminate nuclear weapons by the year 2020 . Geography . Hiroshima is situated on the Ōta River delta , on Hiroshima Bay , facing the Seto Inland Sea on its south side . The river ' s six channels divide Hiroshima into several islets . Climate . Hiroshima has a humid subtropical climate characterized by mild winters and hot humid summers . Like much of the rest of Japan , Hiroshima experiences a seasonal temperature lag in summer , with August rather than July being the warmest month of the year . Precipitation occurs year - round , although winter is the driest season . Rainfall peaks in June and July , with August experiencing sunnier and drier conditions . Wards . Hiroshima has eight wards ( " ku " ) : Demographics . As of 2006 , the city has an estimated population of 1 , 154 , 391 , while the total population for the metropolitan area was estimated as 2 , 043 , 788 in 2000 . The total area of the city is , with a population density of 1275 . 4 persons per km² . The population around 1910 was 143 , 000 . Before World War II , Hiroshima ' s population had grown to 360 , 000 , and peaked at 419 , 182 in 1942 . Following the atomic bombing in 1945 , the population dropped to 137 , 197 . By 1955 , the city ' s population had returned to pre - war levels . Culture . Hiroshima has a professional symphony orchestra , which has performed at Wel City Hiroshima since 1963 . There are also many museums in Hiroshima , including the Hiroshima Peace Memorial Museum , along with several art museums . The Hiroshima Museum of Art , which has a large collection of French renaissance art , opened in 1978 . The Hiroshima Prefectural Art Museum opened in 1968 , and is located near Shukkei - en gardens . The Hiroshima City Museum of Contemporary Art , which opened in 1989 , is located near Hijiyama Park . Festivals include Hiroshima Flower Festival and Hiroshima International Animation Festival . Hiroshima Peace Memorial Park , which includes the Hiroshima Peace Memorial , draws many visitors from around the world , especially for the Hiroshima Peace Memorial Ceremony , an annual commemoration held on the date of the atomic bombing . The park also contains a large collection of monuments , including the Children ' s Peace Monument , the Hiroshima National Peace Memorial Hall for the Atomic Bomb Victims and many others . Hiroshima ' s rebuilt castle ( nicknamed " Rijō " , meaning " Koi Castle " ) houses a museum of life in the Edo period . Hiroshima Gokoku Shrine is within the walls of the castle . Other attractions in Hiroshima include Shukkei - en , Fudōin , Mitaki - dera , and Hijiyama Park . Cuisine . Hiroshima is known for okonomiyaki , cooked on a hot - plate ( usually in front of the customer ) . It is cooked with various ingredients , which are layered rather than mixed together as done with the Osaka version of okonomiyaki . The layers are typically egg , cabbage , bean sprout s ( moyashi ) , sliced pork / bacon with optional items ( mayonnaise , fried squid , octopus , cheese , mochi , kimchi , etc . ) , and noodles ( soba , udon ) topped with another layer of egg and a generous dollop of okonomiyaki sauce ( Carp and Otafuku are two popular brands ) . The amount of cabbage used is usually 3 to 4 times the amount used in the Osaka style , therefore arguably a healthier version . It starts out piled very high and is generally pushed down as the cabbage cooks . The order of the layers may vary slightly depending on the chef ' s style and preference , and ingredients will vary depending on the preference of the customer . Media . The Chugoku Shimbun is the local newspaper serving Hiroshima . It publishes both morning paper and evening editions . Television stations include Hiroshima Home Television , Hiroshima TV , TV Shinhiroshima , and the RCC Broadcasting Company . Radio stations include Hiroshima FM , Chugoku Communication Network , FM Fukuyama , FM Nanami , and Onomichi FM . Hiroshima is also served by NHK , Japan ' s public broadcaster , with television and radio broadcasting . Education . Hiroshima University was established in 1949 , as part of a national restructuring of the education system . One national university was set up in each prefecture , including Hiroshima University , which combined eight existing institutions ( Hiroshima University of Literature and Science , Hiroshima School of Secondary Education , Hiroshima School of Education , Hiroshima Women ' s School of Secondary Education , Hiroshima School of Education for Youth , Hiroshima Higher School , Hiroshima Higher Technical School , and Hiroshima Municipal Higher Technical School ) , with the Hiroshima Prefectural Medical College added in 1953 . International relations . Twin towns and sister cities . Hiroshima has six overseas sister cities : Within Japan , Hiroshima has a similar relationship with Nagasaki .