The rulers  of Japan have been its Emperors, whether effectively or nominally, for its entire recorded history. These include the ancient legendary emperors, the attested but undated emperors of the Yamato period (early fifth to early 6th centuries), and the clearly dated emperors of 539 to the present. Political power was held in various eras by regents and shōguns, and since 1946 has been exercised exclusively by the Prime Minister as leader of a representative government.
| Period | Nominal rulers | Effective powers | c | 
| Foundation–Heian period | Emperors, 660 BC (traditional)–present
 | Emperors Soga clan, 530s–645
 Fujiwara clan, 850s–1070
 Minamoto clan, 960s–1192
 Taira clan, 1160s–1185
 | Nara Kyoto
 | 
| Kamakura period | Minamoto no Yoritomo, 1147–1199 Kamakura shōguns (successors of Minamoto clan), 1192–1333Regents of Kamakura shogunate, 1203–1333
 | Kamakura Kyoto
 | 
| Kenmu Restoration | Emperor Go-Daigo (descendant of Minamoto clan), 1333–1336 Ashikaga Takauji (descendant of Minamoto clan), 1333–1336
 | Kyoto | 
| Muromachi period | Ashikaga shōguns (successors of Kamakura shōguns), 1338–1568 (1573) Northern Court Emperors, 1336–1392
 Sakai Kubō (Hosokawa and Miyoshi clan), 1527–1532
 Regional daimyōs, during Sengoku period
 | Kyoto | 
| Azuchi–Momoyama period | Oda Nobunaga, 1568–1582 Toyotomi Hideyoshi, 1582–1598
 Five Commissioners, 1585–1600
 Council of Five Elders, 1598–1600
 | Azuchi Kyoto
 Osaka
 | 
| Edo period | Tokugawa shōguns (descendants of Minamoto clan), 1603–1867 Tairō of Tokugawa shogunate, 1636–1865
 | Edo (Tokyo) | 
| After Meiji restoration | Emperors, 1867–1947 Kido Takayoshi, 1867–1877
 Saigō Takamori, 1867–1873
 Ōkubo Toshimichi, 1867–1878
 Prime Ministers, 1885–present
 Supreme Commander of the Allied Powers, 1945–1952
 | Tokyo | 
See also