From here, Japan began to send aid, materials and supplies to Serbia through the Mediterranean Sea and Russia, growing the relationship between the two countries.

Japan also opposed what they called "brutal occupation" by the Austrians and Bulgarians after they invaded Serbia in 1915.

Japan had supported Germany and its ally, making the relationship between the two drop to the lowest point in its history.

Josip Broz Tito assumed power after the collapse of the Kingdom and quickly restored back relations with Japan, which was now crumbling.

Despite having a long and quality relations with Serbia, Japan, however, also had supported the independence of the disputed territory of Kosovo.