What is history: it is the echo of the past to the future, the reflection of the future on the past. - Hugo
In the fifth year of Keicho(1600), Tokugawa Ieyasu defeated the Western Army at the Battle of Sekigahara, achieving a historic victory and ascending to the throne of Japan's de facto supreme ruler. The main generals of the Western Army, Ishida Sansei, Governor Konishi, and Ankokuji Keisuke were beheaded by Tokugawa Ieyasu after the war.
However, some people feel strange that the Western Army in the Battle of Sekigahara claimed to have hundreds of thousands of troops, and the actual number of troops participating in the battle was also about 100,000, and the strength of the Western Army was probably dozens of people. So why did Tokugawa Ieyasu kill only Ishida Mitsunari, Governor Konishi, and Ankokuji Keijo after the war?
Although Tokugawa Ieyasu won the Battle of Sekigahara, he was not strong enough to kill all the daimyōs of the Western Army. Even in the heyday of the Edo shogunate, the Tokugawa family was unable to eliminate all foreign daimyōs, not to mention Tokugawa Ieyasu, who had two titular lords on his head at that time.
Because of this, After the Battle of Sekigahara, Tokugawa Ieyasu could only kill a few daimyo who had to be killed or who could play a warning role. Most of the Western Daimyo were punished by the reduction or confiscation of territory after the war, but not many were actually killed, and some of the Western Army appeared again during the Osaka Front.
Ishida Sansei is the de facto commander-in-chief of the Western Army, and at the same time the most hated daimyō of the Western Army, especially the Toyotomi family, which constitutes the main force of the Eastern Army, hates him to the bone, and many of them join the Eastern Army in order to kill Ishida Sansei. Ishida Misei is a daimyō who Tokugawa Ieyasu must kill.
Both Konishi and Ishida Arehida were representatives of the Toyotomi family's Bunji faction, and the arbitrary faction's hatred for him was second only to Ishida's. Coupled with the fact that Governor Konishi's domain was located in the Kyushu region, where Tokugawa Ieyasu's control was weak, it was necessary to win over the Daimyo of the Eastern Army in the Kyushu region by killing Governor Konishi.
Although the actual commander of the Western Army was Ishida Misei, the titular general would be Maori Keigen. Without the support of the Maori family, Ishida Sansei could not afford to pull up the main force of the Western Army of about 100,000. However, due to the strength of the Maori family and the special contribution of the "Three Gods", Tokugawa Ieyasu could not kill Maori Keigen.
As a result, Keicho Ankokuji, a Maori courtier who contacted Ishida Sansei on behalf of Maori Huiyuan, became a scapegoat for the Maori family and was said to be the mastermind of the Western Army at the Battle of Sekigahara. It can be said that Tokugawa Ieyasu killed Ankokuji Keijo to warn Maori Huiyuan, and many people in later generations felt that Ankokuji Keijun was wronged.