æt ðə stˈɑːɹt ʌv wˈɜːld wˈɔːɹ ˈaɪ, tsuːʃˈiːmə wʌz ɪnˈɪʃəli ɐsˈaɪnd tə pɐtɹˈoʊl ʌvðə sˈiː lˈeɪnz bᵻtwˌiːn bˈoːɹnɪˌoʊ ænd tˈiːmoːɹ ɐɡˈɛnst dʒˈɜːmən kˈɑːmɜːs ɹˈeɪdɚz æz pˈɑːɹt ʌv dʒəpˈænz kˌɑːntɹɪbjˈuːʃən tə ðɪ ˈælaɪd wˈɔːɹ ˈɛfɚt ˌʌndɚ ðɪ ˈæŋɡloʊdʒˌæpənˈiːz ɐlˈaɪəns.
At the start of World War I, Tsushima was initially assigned to patrol of the sea lanes between Borneo and Timor against German commerce raiders as part of Japan's contribution to the Allied war effort under the Anglo-Japanese Alliance.