There are many theories about in what year the Kamakura period truly began, of which the 1192 theory, the year MINAMOTO no Yoritomo was made Shogun (Seii taishogun (literally, "great general who subdues the barbarians")), is the orthodox view, but in addition, theories include: the 1180 theory, focusing on Yoritomo raising his army and leading his gokenin (lower-ranking warrior vassals) into battle to destroy the Taira clan, and also establishing the Samurai Dokoro (Board of Retainers, which oversaw rewards for service); the 1183 theory, in which the key moment is the official recognition of the shogunate's right to control Eastern Japan (everything along the Tokaido and Tosando highways) proclaimed by the imperial court in the tenth month; the 1185 theory, which focuses on Yoritomo's use of his struggle to destroy his younger brother MINAMOTO no Yoshitsune as a pretext to usurp the right to appoint and control the offices of shugo (provincial governor) and jito (estate steward); the 1190 theory, in which it was Yoritomo's visit to the capital and subsequent court appointments to Gon Dainagon (Deputy Major Counselor) and Ukone Taisho (Commander of the Guardsmen of the Right) that is considered the decisive moment; and a handful even believe it wasn't until 1196 that the Kamakura period truly began.
始期については、従来源頼朝が将軍（征夷大将軍）に任じられた1192年とするのが一般的であるが、頼朝が平家打倒のために挙兵し御家人を統率する侍所を設置した1180年説、寿永二年十月宣旨で東国（東海道および東山道）の支配権を朝廷に公認された1183年説、対立する弟・源義経追討の名目で惣追捕使（後の守護）・地頭の設置権を獲得した1185年説、頼朝が上洛し権大納言・右近衛大将に任命された1190年説、また一部では1196年説など様々な考え方がある。