Japanese-style castles in the territories he conquered. Ulsan castle was one of such fortresses and the site of Kiyomasa's most famous battle — the Siege of Ulsan on December 22, 1597. Kiyomasa led the defense of the castle, successfully holding at bay Chinese general Yang Hao's army, which numbered 60,000. He defended the castle until November 23, 1598. However, his bravery was not reported to Hideyoshi by his rival and superior Ishida Mitsunari. Hideyoshi recalled him to Kyōto. As did a number of other daimyōs who participated in the invasion of Korea, he took a group of captive Korean potters back to his fief in Kyūshū. Sekigahara campaign After Hideyoshi's death, Kiyomasa clashed with Ishida Mitsunari, and started approaching Tokugawa Ieyasu. both Tokugawa Ieyasu and Ishida Mitsunari courted his support. Ishida's so-called Western forces might well have gotten themselves a formidable warrior were it not for two factors that decided Kiyomasa, otherwise a Toyotomi loyalist. First, the Western forces were led by Ishida Mitsunari, whom Katô loathed as a civilian interloper and had quarreled with during the Korean campaign; and second, the Western forces included Konishi Yukinaga. Although Konishi's navy had aided Kiyomasa quite a bit at the Siege of Ulsan, the two men despised each other as much as ever. Katô joined with Tokugawa and during the Sekigahara campaign (August–October 1600) fought Ishida's allies on Kyushu and took a number of Konishi's castles. He was preparing to invade the Shimazu domain when the campaign ended and Ieyasu ordered him to stand down. For his service, Katô was awarded the other half of Higo (formerly owned by Konishi, who was executed in the wake of Sekigahara), bringing his income to nearly 500,000 koku. Death In his later years, Kiyomasa tried to work as a mediator for the increasingly complicated relationship between Ieyasu and Toyotomi Hideyori. In 1611, en route by sea to Kumamoto after one such meeting, he fell ill, and died shortly after his arrival. He was buried at Honmyō-ji temple in Kumamoto, but also has graves in Yamagata Prefecture and Tokyo. Kiyomasa is also enshrined in many Shinto shrines in Japan, including Katō Shrine in Kumamoto. His son, Katō Tadahiro, succeeded him as Higo no kami 肥後守 (provincial governor of Higo), but his fief (Kumamoto) was confiscated, and he was exiled (kaieki; attaindered) in 1632 by Tokugawa Iemitsu on suspicion of conspiring against him, possibly with the likes