It further refined its plans with the outbreak of hostilities with the United States, bent on increasing its geopolitical and ethnic ties with mainland Asia through a vastly expanded rail and marine network, with special emphasis on the Korean peninsula land bridge to connect it with its colonies.[1] To achieve its objectives, Japan's plans called for "a giant leap forward" in its transportation and communications infrastructures, including shinkansen trains, so that it could integrate all of its colonial economies and ensure the transport of war materials and other necessary supplies to and from the home islands.[12] This coincided with the planning and development of the dangan ressha ("bullet train") system by a Japanese chief rail engineer, Shima Yasujiro, who concurred on the links between Tokyo, Korea, and China.[15][16]