A few days ago I stumbled upon a documentary about Templars. The afterwords of the lecturer left a big impression on me: she said that "We have to be modest towards history and grateful towards legends", because history is subject to change as soon as new informations and datas are acquired, and because sometimes the first hint to an interesting fact is because we heard about some weird legend about them that left an impression... I thought that it's a wonderful summary of the "spirit" of the scholar, and I was amused about how this principle applies perfectly to the figure of Nobunaga.
The "Shinchokouki" (信長公記, "Chronicle of Lord Nobunaga"), our favourite resource, mentions her briefly as the "Dosan's daughter to be welcomed as Nobunaga's bride to Owari Province" and no further infos could be found in the next pages, and in the notes of the "Japonius Tyrannus", Lamers dismisses her with a quick and painless "No children were produced by this first marriage, and Kichō was sent back to Mino after Saito Dosan has been killed in 1556 by his own son."
The shocking lack of informations, in fact, is usually seen as consequence of two possible events: one implies a divorce occured as the Saito clan opened hostilities with Nobunaga, the other, the premature death of the princess.
To gather a few more informations I had to try to decipher the Japanese Wikipedia, that gives a few more informations and reference materials.
The first book brought to our attention is the "Minonokuni Shoukyuki" (美濃国諸旧記, "Chronicles of Mino Province"), a record of facts concerning the Toki, Akechi and Saito clans.
Here we got to know about the possible "real name" of Nōhime, reported as Kichō (帰蝶), and we got to know that she was the third daughter of Saito Dosan. Her mother, Omi-no-kata (小見の方, "Lady Omi") was the younger sister of Akechi Mitsutsuna, the father of Mitsuhide. Nōhime and Mitsuhide were in fact cousins, but there are no informations about them spending time together.
The marriage between Nobunaga and Nōhime was celebrated on March 24, 1549. The meeting between Nobunaga and Dosan at Shotokuji is dated 1553.
Yoshitasu rebelled against his father and killed him at the Battle of Nagara River on 1556.
So Nobunaga had to divorce Nōhime, as their marriage had no further reason to exist, expecially given her infertility.
But at this point we are reminded of a few facts.
First, Nobutada was born on 1557 from a concubine of Mino (not from Kitsuno, who's recognized as the mother of Nobukatsu and Gotoku only), and there's evidence that he was adopted by Nōhime so to make him Nobunaga's heir. This is reported on the "Seishu Gunki" (勢州軍記, "Record of Ise Province"), and it's generally considered a strategic move of Nobunaga to ensure himself the role of legittimate ruler of Mino, given Yoshitasu's usurpation. As Nōhime became a connection between Nobunaga and the Saito's bloodline, there was no point for him to divorce her.
Again, further appearances of "Nobunaga's Lawful Wife" (信長内室) could be spotted on the "Akechi Gunki" (明智軍記, "Records of Akechi Mitsuhide"), where she "treated his vassals with many avalons and other delicacies at a banquet held after the suppression of Owari Province to express gratitude for their support for the order of the suppression of Mino Province", on the "Tokitsugu Kyoki" (言継卿記, "Diary of Yamashina Tokitsugu"), which was compiled on 1569, and again on the "Ominokuni Kochishi" (近江國輿地志, "Summary of topography of Omi Province"), compiled on 1568, where there's a mention of Nobunaga and his "wife" (御台所, "Midaidokoro") staying at Jobodaiji.
Furthermore, on the "Myoshinjishi" (妙心寺史, "Chronicle of Myoshinji") is reported that the "wife of Nobunaga" (信長公夫人) organized the first year anniversary of Nobunaga's death on July 20, 1583.
Things became complicated when other kind of attributes come into play.
The above mentioned "Minonokuni Shoukyuki" gave her the Sagiyama-dono ("Lady of Sagiyama Castle") title, implying that at a certain point she lived at Sagiyama Castle. The idea of Nobunaga divorcing from her probably derives from this title, as Sagiyama Castle was presented to Yoshitatsu on 1548 by Dosan, but it's equally possible that she gained this nickname when she escorted her father in there, during one of his temporary refuges.
The "Oda Nobukatsu Bungencho" (織田信雄分限帳, "Registers of vassals of Oda Nobukatsu") mentions a certain Azuchi-dono ("Lady of Azuchi Castle"), who was granted a stipend of 600 kan and that was ranked third on the list of female vassals, the first being Nobukatsu's wife and the second Okazaki-dono (= Gotoku) and that she preceded Okata-dono (= Dota Gozen) in ranking.
As there's no certain proof that Okata (御方, "Milady") refers to Dota Gozen, the theory that this Azuchi-dono may be Nōhime comes from the records of "Ujisatoki" (総見院殿追善記, "The Chronicles of Gamo Ujisato") and "Sokenindono Tsuizenki" (総見院殿追善記, "Chronicles of the Buddhist Services for those resting in Sokenin") that mention Midaidokoro and a certain Kita-no-kata (北の方, "Lady in the Northern Pavillion", which is another title related to a legitimate wife [!]) fleeing from Azuchi castle once the news of the Incident of Honnoji arrived, implying that Nōhime was staying at Azuchi at the time and thus identifying her as "Azuchi-dono".
To this same Azuchi-dono belongs the tomb that is identified as Nōhime's in Sokenin, who died on July 26, 1612 and sports the posthumous name Yokainden Yoshinmyo Daishi (養華院殿要津妙玄大姉)...
As I couldn't find original portraits of Kichō, I used some screenshots from my favourite depictions of the Princess of Mino: the first belongs to the TV special Nōhime and it features Mizuki Arisa, the second is my favourite Natori Yuuko from Oda Nobunaga.
--Speaking of movies, I hope that you may find useful the index of the Nobunaga movies reviews that I just added :3
As this post can be considered in a permanent state of update, feel free to contribute with your opinions, infos and the like on the figure of Nōhime, so to get to know more-- With modesty and gratitude.