generals to reorganize the Turkish army and to supervise the garrison in Constantinople on request of the Ottomans, remarking that "the German flag will soon fly over the fortifications of the Bosphorus", a vital trade artery which accounted for two fifths of Russia's exports. Alliance with Japan Despite his fixation on Russian-German affairs, Sazonov was also mindful of Russian interests in the Far East. In the wake of the disastrous Russo-Japanese War, he steadily made friendly overtures toward Japan. As a result, a secret convention was signed in St. Petersburg on 8 July 1912 concerning the delimitation of spheres of interest in Inner Mongolia. Both powers determined to keep Inner Mongolia politically separate from Outer Mongolia. Four years later, Sazonov congratulated himself on concluding a Russian-Japanese defensive alliance (3 July 1916) aimed at securing the interests of both powers in China. World War I In the run-up to a major military conflict in Europe, another concern of the Russian minister was to isolate Austria-Hungary, mainly by playing the Balkan card against the dwindling power of the Habsburgs. Since Sazonov was moderate in his Balkan politics, his ministry "came under frequent nationalist fire for failing to conform to a rigid pan-Slav line". While the extremist agents like Nicholas Hartwig aspired to solidify the conflicting South Slavic states into a confederacy under the aegis of the Tsar, there is no indication that Sazonov personally shared or encouraged these views. Regardless, both Austria and Germany were persuaded that Russia fomented Pan-Slavism in Belgrade and other Slavic capitals, a belligerent attitude in some measure responsible for the Assassination in Sarajevo and the outbreak of the Great War. Serbia was largely viewed as being within Russia's sphere of influence and there was significant support from the political class and the broader population for the Serbian cause. That caused Russia to defend Serbia against Austria after the assassination of the Austrian Archduke Franz Ferdinand. Sazonov warned Austria in 1914 that Russia, "would respond militarily to any action against the client state." As World War I unwound, Sazonov worked to prevent Romania from joining the Central Powers and wrested in March 1915 an acquiescence from Russia's allies to the post-war occupation of the Bosphorus, Constantinople, and the European side of the Dardanelles. On 1 October 1914 Sazonov gave a written guarantee to Romania that, if the country sided with the Entente, it would be enlarged at the