Akechi Tama (明智たま, Akechi Tama), usually referred to as Hosokawa Gracia (細川ガラシャ, Hosokawa Garasha), (1563 – 25 August 1600) was a member of the aristocratic Akechi family from the Sengoku period. Gracia is best known for her role in the Battle of Sekigahara; Ishida Mitsunari attempted to take her hostage to sway her husband, Hosokawa Tadaoki, into joining his side on the battle. She refused to commit suicide because of her Catholic faith, breaking the code of conduct imposed on women of the samurai class and causing a family retainer to kill her instead, possibly at her request.

She was the daughter of Akechi Mitsuhide and Tsumaki Hiroko, the wife of Hosokawa Tadaoki, and a convert to Catholicism. As the last notable survivor of the Akechi clan, the clan that planned and executed the assassination of Oda Nobunaga, the first "Great Unifier" of Japan, Gracia's death affected both armies. The incident did much damage to Ishida's reputation, which greatly reduced his chances of recruiting more allies, some of whom were also secretly Christians.

She was named Akechi Tama or Tamako at birth; Garasha, the name by which she is known in history, is based upon her Catholic baptismal name, Gracia.

She married Hosokawa Tadaoki at the age of sixteen; the couple had five or six children. In the Sixth Month of 1582, her father Akechi Mitsuhide betrayed and killed his lord, Oda Nobunaga, making the teenage Tama a traitor's daughter. Not wishing to divorce her, Tadaoki sent her to the hamlet of Midono in the mountains of the Tango Peninsula (now in Kyoto Prefecture), where she remained hidden until 1584, until Toyotomi Hideyoshi requested that Tadaoki bring Tama to the Hosokawa mansion in Osaka, where she remained in confinement.

Tama's maid, Kiyohara Kayo, baptized Maria, was from a Catholic family, and her husband repeated to her conversations with his Christian friend Takayama Ukon. In the spring of 1587 Tama managed to secretly visit the Osaka church; a few months later, when she heard that Toyotomi Hideyoshi had issued a proclamation against Christianity, she was determined to be baptized immediately. As she could not leave the house, she was baptized by her maid and received the Christian name "Gracia". She is said to have studied both Latin and Portuguese and to have read and become fascinated with Thomas à Kempis' The Imitation of Christ.

In 1595, Tadaoki's life was in danger because of his friendship with Toyotomi Hidetsugu, and he told Gracia that if he should die she must kill herself. When she wrote asking the priests about the plan, they informed her that suicide was a grave sin. However, the danger passed.

The death of Hideyoshi in 1598 left a power vacuum with two rival factions forming: Tokugawa Ieyasu in the east and Ishida Mitsunari in the west. When Ieyasu went to the east in 1600 leading a large army, including Tadaoki, his rival Ishida took over the impregnable castle in Osaka, the city where the families of many of Hideyoshi's generals resided. Ishida devised a plan to take the family members hostage, thus forcing the rival generals either to ally with him or at least not to attack him.

However, when Ishida attempted to take Gracia hostage, the family retainer Ogasawara Shōsai killed her and then committed seppuku after lighting the mansion on fire. The outrage over her death was so great that Ishida was forced to abandon his plans. Most Japanese accounts state that it was Gracia's idea to order Ogasawara to kill her. However, these accounts were written many decades after the actual death of Gracia. The original Jesuit account written shortly after her death instead states Tadaoki had commanded the servants of his household to kill Gracia if her honor were ever in danger. The servants had seen the attempted kidnapping as such, and acted on this order.