This is coolbert:
This was quite a surprise to me. Came across quite by accident. Japanese involvement in the Great War [WW1] not strictly relegated to the Asian and Pacific theatre.
Japanese naval forces on request entering the fray in the European theatre as well, warships on patrol, escorting commercial vessels and providing protection for same.
"World War One"
"Japan entered World War I on the side of the Allies, against Imperial Germany and Austria-Hungary, as a consequence of the 1902 Anglo-Japanese Alliance."
"In the Siege of Tsingtao, the Japanese Navy helped seize the German naval base of Tsingtao." 
"Concurrently, a battle group was sent to the central Pacific in August and September to pursue the German East Asiatic squadron . . ." 
. . . .
"Following a further request to contribute to the conflict, and the advent of unrestricted submarine warfare by Germany, the Imperial Navy in March 1917 sent a special force of destroyers to the Mediterranean. This force, consisting of one armoured cruiser, Akashi, as flotilla leader, and eight of the Navy's newest destroyers . . . By the end of the war, the Japanese had escorted 788 allied transports. One destroyer, Sakaki, was torpedoed by an Austrian submarine with the loss of 59 officers and men."
"In 1918, ships such as Azuma were assigned to convoy escort in the Indian Ocean between Singapore and the Suez Canal as part of Japan’s contribution to the war effort under the Anglo-Japanese alliance."
Various Imperial German colonial possessions in the Pacific the Japanese gaining dominion over in the aftermath of German surrender.
The Japanese gaining valuable combat experience and for the first time demonstrating a global reach impressive and in keeping with established treaties of mutual aid and support to an ally [Great Britain!
You gotta start somewhere.