Ikoma Chikamasa was a daimyo during the Azuchi-Momoyama period of the 16th century to the Edo period of the 17th century of Japan. He was appointed to one of three chu-rō by Toyotomi Hideyoshi. His father was Ikoma Chikashige.

In 1566, he became a retainer of Nobunaga when Nobunaga attacked Mino Province. He worked under Hashiba Hideyoshi (Toyotomi Hideyoshi) from then on, and was involved in various battles such as the Battle of Nagashino, battle against Ishiyama Hongan-ji and battle against Saika party at Kii Province. In 1582, he served Hideyoshi after Nobunaga died, and was active in several battles such as the Battle of Yamazaki, Battle of Shizugatake, siege of Odawara, and Battle of Bunroku. He was given 171,800 koku at Sanuki Province because of his credit. In Hideyoshi's last years, Chikamasa, Nakamura Kazuuji and Horio Tadaharu

Horio Tadaharu

Horio Tadaharu was a tozama daimyō in the Edo period.His father was Horio Tadauji and his grandfather was Horio Yoshiharu.He was the third leader of the Matsue clan....

 were appointed to three chu-rō and participated in the Toyotomi administration.

In 1600 at the Battle of Sekigahara

Battle of Sekigahara

The , popularly known as the , was a decisive battle on October 21, 1600 which cleared the path to the Shogunate for Tokugawa Ieyasu...

, Chikamasa took part in Ishida Mitsunari's force while his son, Ikoma Kazumasa took part in Tokugawa Ieyasu's force. Chikamasa was at Sanuki, and send off his retainers as his substitute to attack against Tanabe castle at Tango Province. He chose the method to keep Ikoma clan going, even if which force was defeated.

Because Kazumasa took part in Ieyasu's force, Ieyasu let Chikamasa rule his domain before the battle continuously after the battle. Chikamasa took his responsibility for his taking part in Mitsunari's force, and transferred the headship of the family to Kazumasa. He became a priest and withdrew to Mount Koya.

He was permitted to back in Sanuki Province

Sanuki Province

was an old province of Japan on the island of Shikoku, with the same boundaries as modern Kagawa Prefecture. It was sometimes called .It faced the Inland Sea and bordered on Awa and Iyo Provinces. Across Naruto strait it bordered Awaji Province too. Administratively it was included as a part of...

before long. In 1603, he died in Takamatsu castle.