This year will see the observance of various centennials, including the ill-fated Gallipoli campaign in the Dardanelles; the Second Battle of Ypres; and the sinking of the RMS Lusitania with the loss of 1,198 lives.

The war in Europe had a favorable impact on the Tokyo stock market, setting off what was called the Taisen Keiki (the "Great War boom," also known as the "Taisho Bubble"), a business boom that was to last until the crash of March 1920.

It was also in 1915 that Harukichi Yamaguchi, a former fisherman from Awaji Island, founded the organization that bears his name: Yamaguchi-gumi.