The Socialist Federal Republic of Koishi is a nation in Amazonia. It is bordered by Mexico to the North, Kagiyama to the South West, and Brazil to the South East.
The name Koishi (小石) literally means small rock. It was named after explorer and navy admiral Koishi Nobukata (小石 信方). The name was later adopted by the Republic of Koishi in 1819, after declaring independence from the Soga Shogunate.