The rota system, from the Old Church Slavic word for "ladder" or "staircase", was a system of collateral succession practiced (though imperfectly) in Kievan Rus' and later Appanage and early Muscovite Russia, in which the throne passed not linearly from father to son, but laterally from brother to brother (usually to the fourth brother) and then to the eldest son of the eldest brother who had held the throne. The system was rationalised by Yaroslav the Wise, who assigned each of his sons a principality based on seniority, though it predates his reign and was also used among the Norse of the British Isles.
When the Grand Prince died, the next most senior prince moved to Kiev and all others moved to the principality next up the ladder. Only those princes whose fathers had held the throne were eligible for placement in the rota; those whose fathers predeceased their grandfathers were known as izgoi, "excluded" or "orphaned" princes.
The concept was first noted by Sergei Soloviev, and later summed up by Vasily Kliuchevsky, but in the intervening years, the structured and institutionalized rota system they presented has come under criticism by some, who doubt any such succession system to the Kievan throne existed at all. Indeed, scholars such as Sergeevich and Budovnitz argued that the seemingly endless internecide war among the princes of Kiev indicates a total lack of any established succession system. Others have modified the system but not fully abandoned it, such as A. D. Stokes, who denied that there was ever a geographic hierarchy of principalities, although there was a hierarchy of the princes themselves.Janet Martin argued that the system, in fact, worked. She argues that the interprincely wars were not a breakdown or absence of a system, but the further refinement of the system as the dynasty grew in size and relations became more complex. Each new outburst of violence addressed a new problem rather than rehashing old disputes.
The rota system was modified by the princely summit conference held at Liubech in the Chernigov lands in northern Ukraine in 1097. Certain lands were granted as patrimonial lands, that is inherited lands outside the rota system. These lands were not lost by a prince when the Kievan throne became vacant, and they served as core lands that grew up into semi-independent (if not outright independent) principalities in the later centuries of Kievan Rus, leading some historians to argue that Kievan Rus ceased to be a unified state. After this conference, the rota system continued to work within these patrimonial principalities at least up to the Mongol Invasion. The rota system also continued with regard to the Kievan throne after 1113 up to the Mongol Invasion as well.