Initially, the replacement shrine was planned in the Mount Maizuru tunnels. However, the unit in charge of the shrine had no idea how to build one. Tokyo University engineering professor Private First Class Katsukazu Sekino was put in charge. The headquarters asked the advice of several other professors. At the instruction of one of them, the tunnels were split into lightning forms to reduce the impact from bombs. The "Japanese of pure blood" came from youths at the Atami branch of the Railroad Ministry training institutes. Work started in July 1944, but was halted shortly thereafter. Naval tunnel The Imperial Japanese Navy opposed the idea of fighting a battle on Japanese soil. Nonetheless it was allotted a tunnel plan in June 1945. The 300th Division in Yokosuka engaged in building aircraft hangars sent half of its strength to build the naval tunnel. It was intended to be 3.5 km long and was 16 km away from the rest of the complex in Matsushiro. The capacity of the tunnel was approximately 1,000 people. The group managed to dig 100 meters into the ground before the surrender. Comfort women Around the shelters, there were three comfort houses with four to five Korean comfort women servicing them. These were, however, not intended for soldiers, but primarily for supervisors of higher standing within the ranks of the Korean laborers. However, it is rumored that children were chided for staring at soldiers in trucks and women in what appeared to be Chinese clothes. Among these facilities, there was an entertainment room for female staff of a local company. Following its liquidation in 1938, it became in September 1944 an accommodation facility for laborers. In November, a Korean family of five and three comfort women who could not speak Japanese, who were allegedly brought in by Korean authorities to comfort Korean laborers, started a gambling facility in the premises. After the war, the family and others left for home. Location Major Masataka Ida of the Ministry of War of Japan and later of Kyūjō incident fame, proposed the location. After the general staff approved it, the Railway Ministry conducted a survey of the area, finalizing the plans to build the complex. Six advantages of the location were pointed out in Ida's proposition: The widest flat area in Honshu, with an airstrip nearby; Solid substrate suitable for excavation and ability to withstand 10-ton bombs; Completely surrounded by