We always talk about Japan and Italy’s relationship to Germany during World War 2 but what was the relationship between Italy and Japan like?

Japanese relations with Italy can be defined by one rough objective: self-interest.

During Italy's invasion of Ethiopia in 1935-1936, the initial Japanese response was a mix of political indifference to acute outrage at what was perceived as further Western Imperialism in Africa. There were two factions: one faction which saw Italy as a potential ally against the United Kingdom, and the other faction which was virulently opposed to any and all European expansionism whatsoever. This faction was bolstered by the fact that the Italians had reneged on a deal that that the Japanese had made regarding the 1940 Olympics: the Japanese sought to host the 1940 Olympics in Tokyo as part of a diplomatic offensive and thus agreed to have a quid pro quo to support Rome for the 1944 Olympics, but when the Swiss as part of the 50th anniversary of the Olympic committee were thought to be the heavy favorite as the 1944 host, the Italians decided to apply for the 1940 Olympics instead, much to Japanese disgruntlement (Tokyo ended up winning, though after the outbreak of the Sino-Japanese war they were forced to give up their hosting rights to the runner-up Helsinki, which in turn was cancelled after the outbreak of World War II and the Winter War in particular).

However, this changed in the aftermath of British condemnation of the Italian invasion, which the Japanese saw as analogous to the Western condemnation of their invasion of Manchuria during the 1931 Mukden incident and the aftermath leading to the Japanese withdrawal from the League of Nations. Suddenly, Italy, being a (relatively) major naval power in Europe, was courted as a potential ally by Imperial Japan, especially the naval faction.

There were relatively serious talks between Italy and Japan at this point about naval cooperation against Britain: that is, in the event that either went to war against Britain, the other would do their best to interfere with British fleet movements in their respective region, thus preventing Britain from amassing its fleet. However, this ran into several hiccups: first, both sides had a poor impression of the other, with the Italians suspecting the Japanese were primarily interested in copying their technology for Japanese industry, as did many Europeans viewed the Japanese (much like they may view, say, China today). On the other hand, the Japanese had a poor opinion of the Italian fleet capability, especially compared to the much larger Japanese navy. These talks ended up going nowhere, though they did set the foundation for the Tripartite Pact that was signed in 1940 between Germany, Italy, and Japan. The Japanese also hoped the Soviets would be brought into the arrangement as doing so would allow Japan to relax its heightened military activity near the Soviet border with Japanese-controlled China and Korea. However, this would not happen due to German planning.

During the war itself, there were numerous efforts from both the Italians and the Japanese to coordinate activities in the Indian Ocean. However, the loss of the Italian naval bases that gave access to the Indian Ocean made this difficult, combined with Japanese xenophobia that essentially forbid Axis ships from entering the local region of Japanese hegemony. The closest effort was an attempt to defend the Vichy naval bases in Madagascar which fell to Allied attack in 1942. However, this did not work out and ultimately Italian-Japanese cooperation was minimally effective. The collapse of Italy in 1943 essentially ended all such efforts at cooperation and ultimately Italy would declare war on Japan in July of 1945, shortly before the Japanese surrender.

Sources:

Valdo Feretti, Japanese-Italy Naval Relations; 1935-1940

Kiyoshi Aizawa, Japan and the Tripartite Pact

J. Calvitt Clarke III, Alliance of the Colored Peoples: Ethiopia and Japan before World War II