Horio Yoshiharu (1542-1611) (personal name Mosuke) is the founder of Matsue. To say why, we need a brief overview of the period of history he lived in.
Prior of the long period of peace and development in the Edo era (1603-1868), Japan was composed constantly warring fiefdoms, and notable samurai lords such as Toyotomi Hideyoshi, Oda Nobunaga, and Tokugawa Ieyasu gradually gathering enough supporters to become major figures in shaping Japanese history. Their activity eventually led up to the decisive battle of Sekigahara in 1600, and over 200 years of nationwide stability followed.
Yoshiharu was drafted into military service at a young age, when Toyotomi Hideyoshi heard about young Mosuke wrestling with a wild boar. Why he was wrestling with the boar, we can only guess.
These guts proved very useful to Hideyoshi, as Yoshiharu went on to thwart high-profile enemies over the course of Hideyoshi’s campaigns against Oda Nobunaga, and he was awarded land to rule over near Mt. Fuji in the old Totomi Province after major victories. That was how the samurai warlord system worked–if you wanted to rule over multiple fiefdoms, you did so by rewarding the people who serve you. Well-accomplished warriors would rule directly, but still take orders from their overlords. Everyone was happy! If they were samurai, anyway–farmers were probably just happy with whoever wouldn’t terrorize them.
Hideyoshi didn’t live to see the end of the warring states period, though, and after he died Yoshiharu entered Tokugawa Ieyasu’s service, earning property in the old Echizen province facing the Sea of Japan (but still pretty far east of the San’in region). Though he was phasing some of his position over to his son Tadauji at that time, Yoshiharu’s services on and off the battle field were still necessary.
A particularly notable example was at a dinner party he attended with Mizuno Tadashige (an ally) and Kaganoi Shigemochi (a fremeny, if you will–his family had previously served the Oda clan until they surrendered to Hideyoshi and recieved land from him to rule over). Shigemochi got drunk and killed Tadashige, and Yoshiharu therefore killed Shigemochi, thus wiping out the Kaganoi clan and putting the territory fully in Ieyasu’s control. That land would have been in the way of a military manuever enacted soon after, but having Shigemochi out of the way was a big help to Ieyasu.
Though that raised Yoshiharu’s status, he was injured in the battle with Shigemochi, and therefore could not personally partake in the Battle of Sekigahara two months later. Tadauji, however, was present and won honors in his father’s stead. Once Ieyasu took effective control of the country and needed to organize it in such a way that would cement the central government’s control over all the provinces, Horio received his final property to rule over: the Izumo Province.
Yoshiharu and Tadauji hurried out here to the San’in region, stayed in an old castle in present day Yasugi City, and started making plans for building a more suitably located castle. That process is a story for another entry, but you can read about the naming of Matsue right now.
Yoshiharu ruled until he died in 1611, the same year construction on Matsue Castle was completed. He was well-liked and known for having the temperment of a Buddha, and therefore nicknamed “Hotoke no Mosuke” (the Mosuke Buddha).