Complex sentence: In October 1918, Kichisaburo Nomura was appointed captain of "Yakumo" for two months, only one of which he spent on board the vessel, as a political appointment to quality Nomura for flag rank.
Split into simpler sentences: In October 1918, Kichisaburo Nomura was appointed captain of "Yakumo" for two months, only one of which he spent on board the vessel. The posting was a political appointment to quality Nomura for flag rank.