There were eight female imperial reigns (six female emperors including two who reigned twice) in Japan's early history between 593 and 770, and two more in the early modern period (Edo era). Although there were eight reigning empresses, their successors were most often selected from amongst the males of the paternal Imperial bloodline, which is why some conservative scholars argue that the women's reigns were temporary and that male-only succession tradition must be maintained. After many centuries, female reigns came to be officially prohibited only when the Imperial Household Law was issued in 1889 alongside the new Meiji Constitution.
- Empress Jingū r. 206–269 —legendary/mythical; removed from the list of Emperors in the 19th century
- Empress Suiko (554–628), r. 593–628—first ruling empress
- Empress Kōgyoku (594–661), r. 642–645—formerly Princess Takara (Empress Consort of Jomei)
- Empress Saimei (594–661), r. 655–661 (same person as Empress Kōgyoku)
- Empress Jitō (645–702), r. 690–697
- Empress Gemmei (661–721), r. 707–715
- Empress Genshō (680–748), r. 715–724—formerly Princess Hidaka
- Empress Kōken (718–770), r. 749–758
- Empress Shōtoku (718–770), r. 764–770 (same person as Empress Kōken)
- Empress Meishō (1624–1696), r. 1629–1643
- Empress Go-Sakuramachi (1740–1813), r. 1762–1771—most recent ruling empress
In ancient Japan most of empresses consort were princesses, except for Iwa-no hime (empress consort of Nimmyō). After Kōmyō Kōgō (empress consort of Shōmu), daughters of Fujiwara clan or other clans could become empresses consort. Originally Chūgū (中宮) meant the palace for Kōgō, Kōtaigō (皇太后) (Empress Mother/Empress Dowager), or Tai-Kōtaigō (太皇太后) (Grand Empress Mother/Grand Empress Dowager). Until mid-Heian Period, Emperor had only one empress consort, and empress consort was also called Chūgū. Since Emperor Ichijō, because some Emperors had two empresses Consort, one of them was called Kōgō and the another one was called Chūgū. After maiden Princess Yasuko became Kōgō as the mother-in-law (准母) of Emperor Horikawa, maiden princesses also became Kōgō.
List of non-reigning empresses
Kōgō is the title of a non-reigning empress consort. The title, still in use, is generally conferred on an emperor's wife who had given birth to the heir to the throne. The title was first awarded posthumously in 806 to the late mother of Emperor Heizei.
The numbers of kōgō varied, but there was only one Chūgū at a time.
The title kōtaigō was given to the wife of an ex-emperor; and the title tai-kōtaigō came to be used by a dowager empress.
- Ōtomo no Koteko (大伴小手子), also known as Otehime (小手姫), empress-consort of Emperor Sushun, 587–592
- Empress Yamato (倭姫王), empress-consort of Emperor Tenji, 661–671
- Princess Tōchi (十市皇女) (648–678), empress-consort of Emperor Kōbun, 671-672
- Empress Kōmyō (光明皇后) (701–760), empress-consort of Emperor Shōmu, 730–749
- Princess Inoe (井上内親王) (717–775), empress-consort of Kōnin 770–772 (deposed)
- Fujiwara no Otomuro (藤原乙牟漏) (760–790), empress of Kammu 783–790
- Fujiwara no Taishi/Tarashiko (藤原帯子) (?–794), empress of Emperor Heizei (posthumous honor in 806)
- Tachibana no Kachiko (橘嘉智子) (786–850), Empress of Saga 815–823
- Princess Seishi (正子内親王) (810–879), empress of Junna 827–833
- Princess Koshi (高志内親王) (789–809), empress of Junna (posthumous honor in 823)
- Fujiwara no Onshi (藤原穏子) (885–954), empress of Daigo 923–930
- Fujiwara no Anshi (藤原安子) (927–964), empress of Murakami 958–964
- Princess Masako (昌子内親王) (950–999), empress of Reizei 967–973
- Fujiwara no Kōshi (藤原媓子) (947–979), empress of Enyū 973–979
- Fujiwara no Junshi/Nobuko (藤原遵子) (957–1017), empress (kōgō) of Emperor Enyū 982–1000
- Fujiwara no Teishi (藤原定子) (977–1001), empress (chūgū) of Emperor Ichijō 990–1000, Empress (kōgō) of Ichijō 1000–1001
- Fujiwara no Shōshi (藤原彰子) (988–1074), Empress (chūgū) of Ichijō 1000–1012
- Fujiwara no Kenshi (藤原妍子) (994–1027), Empress (Chūgū) of Emperor Sanjō 1012–1018
- Fujiwara no Seishi (藤原娍子) (972–1025), Empress (Kōgō) of Sanjō 1012–1025
- Fujiwara no Ishi (藤原威子) (999–1036), Empress (Chūgū) of Emperor Go-Ichijō 1018–1036
- Princess Teishi (禎子内親王) (1013–1094), Empress (Chūgū) of Go-Suzaku 1037, Empress (Kōgō) of Emperor Go-Suzaku 1037–1051
- Fujiwara no Genshi (藤原嫄子) (1016–1039), Empress (Chūgū) of Go-Suzaku 1037–1039
- Princess Shoshi (章子内親王) (1026–1105), Empress (Chūgū) of Emperor Go-Reizei 1046–1068
- Fujiwara no Hiroko (藤原寛子) (1036–1127), Empress (Kōgō) of Go-Reizei 1051–1068, Empress (Chūgū) of Go-Reizei 1068–1069
- Fujiwara no Kanshi (藤原歓子) (1021–1102), Empress (Kōgō) of Go-Reizei 1068–1074
- Princess Kaoruko (馨子内親王) (1029–1093), Empress (Chūgū) of Go-Sanjō 1069–1074, Empress (Kōgō) of Go-Sanjō 1074–1093
- Fujiwara no Kenshi (藤原賢子) (1057–1084), Empress (Chūgū) of Emperor Shirakawa 1074–1084
- Princess Teishi/Yasuko (媞子内親王) (1076–1096), Empress (Chūgū) as mother-in-law (准母) of Emperor Horikawa 1091–1093
- Princess Tokushi/Atsuko (篤子内親王) (1060–1114), Empress (Chūgū) of Horikawa 1093–1114
- Princess Reishi (令子内親王) (1078–1144), Empress (Kōgō) as mother-in-law (准母) of Emperor Toba 1108–1134
- Fujiwara no Shōshi/Tamako (藤原璋子) (1101–1145), Empress (Chūgū) of Toba 1118–1124
- Fujiwara no Kiyoko (藤原聖子) (1121–1182), Empress (Chūgū) of Emperor Sutoku 1130–1141
- Fujiwara no Yasuko (藤原泰子) (1095–1156), Empress (Kōgō) of Emperor Toba 1134–1139
- Fujiwara no Nariko (藤原得子) (1117–1160), Empress (Kōgō) of Toba 1142–1149
- Fujiwara no Tashi/Masaruko (藤原多子) (1140–1202), Empress (Kōgō) of Emperor Konoe 1150–1156
- Fujiwara no Teishi/Shimeko (藤原呈子) (1131–1176), Empress (Chūgū) of Konoe 1150–1156, Empress (Kōgō) of Emperor Konoe 1156–1158
- Fujiwara no Kinshi (藤原忻子) (1134–1209), Empress (Chūgū) of Go-Shirakawa 1156–1159, Empress (Kōgō) of Emperor Go-Shirakawa 1159–1172
- Princess Tōshi/Muneko (統子内親王), unmarried Empress (Kōgō) 1158–1159
- Princess Yoshiko (姝子内親王) (1141–1176), Empress (Chūgū) of Emperor Nijō 1159–1162
- Fujiwara no Ikushi (藤原育子), Empress (Chūgū) of Nijō 1162–1172, Empress (Kōgō) of Emperor Nijō 1172–1173
- Taira no Tokushi/Noriko (平徳子) (1155–1214), Empress (Chūgū) of Emperor Takakura 1172–1181
- Princess Sukeko (亮子内親王) (1147–1216), Empress (Kōgō) as mother-in-law (准母) of Emperor Antoku and Emperor Go-Toba 1182–1187
- Fujiwara no Ninshi/Tōko (藤原任子) (1173–1240), Empress (Chūgū) of Go-Toba 1190–1200
- Princess Noriko (範子内親王) (1177–1210), Empress (Kōgō) as mother-in-law (准母) of Emperor Tsuchimikado 1198–1206
- Fujiwara no Reishi (藤原麗子) (1185–1243), Empress (Chūgū) of Tsuchimikado 1205–1210
- Princess Shōshi (昇子内親王) (1195–1211), empress (kōgō) as mother-in-law (准母) of Emperor Juntoku, 1208–1209
- Fujiwara no Ritsushi (藤原立子) (1192–1248), empress-consort (chūgū) of Emperor Juntoku, 1211–1222
- Princess Hōshi/Kuniko (邦子内親王) (1209–1283), Empress (Kōgō) as mother-in-law (准母) of Emperor Go-Horikawa 1221–1224
- Fujiwara no Ariko (藤原有子) (1207–1286), empress-consort (chūgū) of Emperor Go-Horikawa, 1223–1226; empress-consort (kōgō) of Go-Horikawa, 1226–1227
- Fujiwara no Coshi (藤原長子) (1218–1275), empress-consort (chūgū) of Go-Horikawa, 1226–1229
- Fujiwara no Shunshi/Yoshiko (藤原竴子) (1209–1233), empress-consort (chūgū) of Emperor Go-Horikawa, 1230–1233
- Princess Rishi (利子内親王) (1197–1251), Empress (Kōgō) as mother-in-law (准母) of Emperor Shijō 1233–1239
- Fujiwara no Kitsushi/Yoshiko (藤原姞子) (1225–1292), Empress (Chūgū) of Emperor Go-Saga 1242–1248
- Princess Teruko (曦子内親王) (1224–1262), unmarried Empress (Kōgō) 1248–1251
- Fujiwara no Kōshi/Kimiko (藤原公子) (1232–1304), Empress (Chūgū) of Emperor Go-Fukakusa 1257–1259
- Fujiwara no Saneko (藤原佶子) (1245–1272), Empress (Chūgū) of Kameyama 1261, Empress (Kōgō) of Emperor Kameyama 1261–1272
- Fujiwara no Kishi (藤原嬉子) (1252–1318), Empress (Chūgū) of Emperor Kameyama 1261–1268
- Princess Reishi (姈子内親王) (1270–1307), unmarried Empress (Kōgō) 1285–1291
- Fujiwara no Shōshi (1271–1342), Empress (Chūgū) of Emperor Fushimi 1288–1298
- Fujiwara no Kinshi (藤原忻子) (1283–1352), Empress (Chūgū) of Emperor Go-Nijō 1303–1310
- Princess Shōshi (奬子内親王) (1286–1348), unmarried Empress (Kōgō) 1319
- Saionji no Kishi (西園寺禧子) (1303–1333), Empress (Chūgū) of Emperor Go-Daigo 1319–1333
- Princess Junshi (珣子内親王) (1311–1337), Empress (Chūgū) of Emperor Go-Daigo 1333–1337
- unknown, Empress (Chūgū) of Emperor Chōkei
- Minamoto no Masako (源和子) (1607–1678), Empress (Chūgū) of Emperor Go-Mizunoo 1624–1629
- Fujiwara no Fusako (藤原房子) (1653–1712), Empress (Chūgū) of Emperor Reigen 1683–1687
- Princess Yukiko (幸子女王) (1681–1720), Empress (Chūgū) of Emperor Higashiyama 1708–1710
- Princess Yoshiko (欣子内親王) (1779–1846), empress-consort (Chūgū) of Emperor Kōkaku 1794–1820
- Fujiwara no Tsunako (藤原繋子) (1798–1823), Empress (Kōgō) of Ninkō (posthumous honor in 1824)
- Empress Dowager Eishō (英照皇太后), empress-consort of Emperor Kōmei
- Empress Shōken (昭憲皇太后), empress-consort of Emperor Meiji
- Empress Teimei (貞明皇后), empress-wife of Emperor Taisho
- Empress Kōjun (香淳皇后), empress-wife of Emperor Shōwa
- Empress Michiko, empress-wife of Emperor Akihito
- "Life in the Cloudy Imperial Fishbowl," Japan Times. March 27, 2007.
- Nussbaum, Louis-Frédéric. (2005). "Kōgō" in Japan Encyclopedia, p. 543, p. 543, at Google Books.
- Ponsonby-Fane, Richard. (1959). The Imperial Family, p. 318.
- Nussbaum, "Chūgū" at p. 127, p. 127, at Google Books.
- Ponsonby-Fane, pp. 300–302.
- Jochi Daigaku. (1989). Monumenta Nipponica, Vol. 44, p. 455.
- Kawamata municipal website: 絹製品
- Ponsonby-Fane, Richard. (1915). The Imperial Family of Japan, p. x.