Chitose Air Base , is a Japan Air Self-Defense Force base located in Chitose, Hokkaidō, adjacent to New Chitose Airport. It is the JASDF's primary base in northern Japan and tasked with monitoring Japan's maritime borders with Russia. It was also Hokkaidō's primary civilian airport until the opening of New Chitose Airport in 1988. Together, these two jointly operated and connected airports create one of the largest regional airports in Japan.