The Republic of Japan Army (ROJA; Japanese: 日本陸軍の共和国, Nihonrikugun no Kyōwakoku), also known as the West Japanese Army (WJA; Japanese: 西日本軍, Nishinihon-gun), is the main branch of the Republic of Japan Armed Forces responsible for land-based military operations. It is the army of West Japan. The ROJA was created on July 1, 1954.

The WJA's primary opponent is the Japanese People's Ground Self-Defense Force, the de facto army of East Japan, with other major threats including the Korean People's Army, People's Liberation Army, and American People's Army. The largest of the three services of the West Japanese armed forces, the Republic of Japan Army is tasked with maintaining internal and external security in West Japan and operates under the command of the chief of the ground staff, based in the city of Osaka. The present chief of the ground staff is General ???? (Japanese: ????).

The JGSDF numbered around 85,000 soldiers in 2014.

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