Why November 1915 changes Japan's calculation

The proposed decision follows Tsingtao, the Falklands, Dogger Bank, and months of debate over Japan's role in the war. By November 1915, few German surface raiders remain to require Japanese heavy ships in the Pacific. Keeping the fleet at home would preserve strength against the perceived American threat, while sending it to Europe could strengthen the British alliance and establish Japan's standing through frontline service. Allowing roughly eleven months for debate makes this political reversal more plausible than an immediate decision after the Falklands. The choice depends on accepting that British support would provide greater security than retaining every heavy ship at home.