The alliance debate was not based only on Pacific geography. Japan had served alongside Britain throughout the First World War: Japanese forces captured German-held Tsingtao, naval units supported anti-submarine operations in the Mediterranean, and Japan offered capital ships to the Grand Fleet after Jutland. Australia and New Zealand could therefore cite a record of practical wartime cooperation when they called Japan a reliable and loyal ally. Their 1921 position looked more defensible to contemporaries than a later Second World War map might suggest.
Notable Point · 39:27-40:17
Why Australia and New Zealand trusted Japan in 1921
Japan's capture of German-held Tsingtao, Mediterranean anti-submarine service, and offer of capital ships after Jutland underpinned dominion confidence in the alliance.