Toyotomi clan in the context of Matsudaira Motoyasu

Tokugawa Ieyasu (born Matsudaira Takechiyo; January 31, 1543 – June 1, 1616) was a Japanese samurai, daimyo, and the founder and first shōgun of the Tokugawa shogunate of Japan, which ruled from 1603 until the Meiji Restoration in 1868. He was the third of the three "Great Unifiers" of Japan, along with his former lord Oda Nobunaga and fellow Oda subordinate Toyotomi Hideyoshi. The son of a minor daimyo, Ieyasu once lived as a hostage under daimyo Imagawa Yoshimoto on behalf of his father. He later succeeded as daimyo after his father's death, serving as ally, vassal, and general of the Oda clan, and building up his strength under Oda Nobunaga.

After Oda Nobunaga's death, Ieyasu was briefly a rival of Toyotomi Hideyoshi, before declaring his allegiance to Toyotomi and fighting on his behalf. Under Toyotomi, Ieyasu was relocated to the Kanto plains in eastern Japan, away from the Toyotomi power base in Osaka. He built his castle in the fishing village of Edo (now Tokyo). He became the most powerful daimyo and the most senior officer under the Toyotomi regime. Ieyasu preserved his strength during Toyotomi's failed attempts to conquer Korea. After Hideyoshi's death and the Battle of Sekigahara, Ieyasu seized power in 1600.

Mon (紋, [mõ̞ꜜɴ]), also called monshō (紋章), mondokoro (紋所), and kamon (家紋), are Japanese emblems used to decorate and identify an individual, a family, or (more recently) an institution, municipality or business entity. While mon is an encompassing term that may refer to any such device, kamon and mondokoro refer specifically to emblems that are used to identify a family. An authoritative mon reference compiles Japan's 241 general categories of mon based on structural resemblance (a single mon may belong to multiple categories), with 5,116 distinct individual mon.

It is well acknowledged that there are a number of lost or obscure mon. Among mon, the mon officially used by the family is called jōmon (定紋). Over time, new mon have been created, such as kaemon (替紋), which is unofficially created by an individual, and onnamon (女紋), which is created by a woman after marriage by modifying part of her original family's mon, so that by 2023 there will be a total of 20,000 to 25,000 mon.

The siege of Osaka (大坂の役, Ōsaka no Eki; or, more commonly, 大坂の陣 Ōsaka no Jin) was a series of battles undertaken by the Japanese Tokugawa shogunate against the Toyotomi clan, and ending in that clan's destruction. Divided into two stages, the winter campaign and the summer campaign, it lasted from 1614 to 1615. The siege put an end to the last major armed opposition to the establishment of the Tokugawa shogunate. The end of the conflict is sometimes called the Genna Armistice (元和偃武, Genna Enbu), because the era name was changed from Keichō to Genna immediately following the siege.

Oeyo (於江与), Gō (江), Ogō (小督) or Satoko (達子) : 1573 – September 15, 1626) was a noblewoman in Japan's Azuchi–Momoyama period and early Edo period. She was a daughter of Oichi and the sister of Yodo-dono and Ohatsu. When she rose to higher political status during the Tokugawa shogunate, she took the title of "Ōmidaidokoro". Following the fall of the Council of Five Elders, Oeyo and her sisters were key figures in maintaining a diplomatic relationship between the two most powerful clans of their time, Toyotomi and Tokugawa. Due to her great contributions to politics at the beginning of the Edo period she was posthumously inducted into the Junior First Rank of the Imperial Court, the second highest honor that could be conferred by the Emperor of Japan.

Oeyo married three times, first to Saji Kazunari, her cousin, then to Toyotomi Hideyoshi's nephew, Toyotomi Hidekatsu. She had a daughter with Hidekatsu named Toyotomi Sadako, who later married Kujō Yukiie. Her third and last husband Tokugawa Hidetada became the second Tokugawa shōgun. She was also the mother of his successor Iemitsu, the third shōgun. Her children included Senhime, Tamahime, Katsuhime, Hatsuhime, Takechiyo (Iemitsu), and Tadanaga. Hatsuhime was adopted by Oeyo's sister Ohatsu, who was married to Kyōgoku Takatsugu.

Yodo-dono (淀殿) or Yodo-gimi (淀君; [jo.do(ꜜ).ɡʲi.mʲi, -ŋʲi.mʲi], 1569 – June 4, 1615), also known as Lady Chacha (茶々; [tɕaꜜ.tɕa]), was a Japanese historical figure in the late Sengoku period. She was the concubine and the second wife of Japanese ruler Toyotomi Hideyoshi. As the mother of his son and successor Hideyori, she acted as Hideyori's guardian in the restoration of the Toyotomi clan after the fall of the Council of Five Elders, and alongside her son, led the last anti-Tokugawa shogunate resistance in the siege of Osaka.

She was the daughter of Oichi and sister of Ohatsu and Oeyo. When her two younger sisters became prominent members linked to the Tokugawa clan, she and her sisters became vital to maintaining the diplomatic relations between the two most powerful clans of the time, Toyotomi and Tokugawa. Her sister, Oeyo, was the wife of the second shogun, Tokugawa Hidetada, and matriarch of the successive shoguns' lineage, thus receiving the political title Omidaidokoro.

Ohatsu (お初) or Ohatsu-no-kata (お初の方) (1570 – September 30, 1633) was a prominently placed figure in the late Sengoku period. She was daughter of Oichi and Nagamasa Azai, and the sister of Yodo-dono and Oeyo. Alongside her sisters, she was active in the political intrigues of her day. Ohatsu's close family ties to both the Toyotomi clan and the Tokugawa clan uniquely positioned her to serve as a conduit between the rivals. She acted as a liaison until 1615 in the siege of Osaka, when the Tokugawa eliminated the Toyotomi.