the more secure and populous counties (xiàn). As the commanderies formed the front lines between the major states, however, their military strength and strategic importance were typically much greater than the counties'. Over time, however, the commanderies were eventually developed into regular provinces and then discontinued entirely during the Tang dynasty reforms. Japan The European concept of marches applies just as well to the fief of Matsumae clan on the southern tip of Hokkaidō which was at Japan's northern border with the Ainu people of Hokkaidō, known as Ezo at the time. In 1590, this land was granted to the Kakizaki clan, who took the name Matsumae from then on. The Lords of Matsumae, as they are sometimes called, were exempt from owing rice to the shōgun in tribute, and from the sankin-kōtai system established by Tokugawa Ieyasu, under which most lords (daimyōs) had to spend half the year at court (in the capital of Edo). By guarding the border, rather than conquering or colonizing Ezo, the Matsumae, in essence, made the majority of the island an Ainu reservation. This also meant that Ezo, and the Kurile Islands beyond, were left essentially open to Russian colonization. However, the Russians never did colonize Ezo, and the marches were officially eliminated during the Meiji Restoration in the late 19th century, when the Ainu came under Japanese control, and Ezo was renamed Hokkaidō, and annexed to Japan. Persia (Sassanid Empire) Roman Empire Ukraine Ukraine, from the Moscow-centric Russian viewpoint, functioned as a "borderland" or "march" and gained its current name, which is derived from a Slavic term of the same meaning (see above for similar in Slovenia, etc.), ultimately from this function. This, though, was merely a continuation of a semi-formal arrangement with the Poles, before escalating feuds, political infighting in Poland, and religious differences (mainly Eastern Orthodox vs. Roman Catholic) saw a loose coalition of Ukrainian lords and independent landowners collectively known as the Cossacks shift to ally with the Russian Empire. The Cossacks became a significant part of Russian military history in their role as military border/buffer-troops in the Wild Fields of Ukraine. The Tatar slave raids in East Slavic lands brought considerable devastation and depopulation to this area prior to the rise of the Zaporozhian Cossacks. As settlement advanced and the borders moved, the Tsars transferred or formed Cossack units to perform similar functions on other borderlands/marches further south and