Asahito (Japanese: 朝仁), posthumously honored as Emperor Higashiyama (東山天皇, Higashiyama-tennō; 21 October 1675 – 16 January 1710), was the 113th emperor of Japan, according to the traditional order of succession. Higashiyama's reign spanned the years from 1687 through to his abdication in 1709 corresponding to the Genroku era of the Edo period. The previous hundred years of peace and seclusion in Japan had created relative economic stability. The arts flourished, including theater and architecture.

Before Higashiyama's ascension to the Chrysanthemum Throne, his personal name (imina) was Asahito (朝仁) or Tomohito. Tomohito was born on October 21, 1675, and was the fifth son of Emperor Reigen; his birth mother was a lady-in-waiting named Matsuki Muneko. While Prince Tomohito was the son of a secondary consort, he was adopted by empress Takatsukasa Fusako (chief consort or Chūgū). Tomohito's Imperial family lived with him in the Dairi of the Heian Palace. Events that took place before Tomohito became Crown Prince include a great flood that devastated Edo, a great famine that devastated Kyoto, and the Great Tenna Fire in Edo. The Shingon Buddhist temple Gokoku-ji was also founded in Edo where it remains today as one of the few sites in Tokyo that survived World War II. Tomohito-shinnō was proclaimed Crown prince in 1682, and given the pre-accession title of Go-no-miya (五宮). For the first time in over 300 years a ceremonial investiture was held for the occasion. A fire burned the Kyoto Imperial Palace to ashes in 1684 prompting reconstruction that took a year to complete. The effects from this fire on the Imperial family, if any, are unknown. Emperor Reigen's brother, former-Emperor Go-Sai, died on March 26, 1685, and a great comet was observed crossing the night sky.

Prince Tomohito acceded to the throne on May 2, 1687, as Emperor when his father abdicated in his favor, the era's name was changed from Jōkyō to Genroku to mark this event. While he held the political title of Emperor, it was in name only as the shoguns of the Tokugawa family controlled Japan. Initially, Emperor Reigen continued to rule in Higashiyama's name as a Cloistered Emperor as had been done in the Heian period. While this move caused trouble by provoking the ruling shogunate, Higashiyama's gentle character helped to improve relations with the Shōgun. This warmed relationship caused imperial property to be increased, and repairs carried out on Imperial mausoleums. Reigen meanwhile lived out his retirement in the Sentō-gosho (the palace for an ex-Emperor), and is now known for being the last "Cloistered Emperor" of Japan. On December 20, 1688, the esoteric Daijō-sai ceremony was revived because of the shogunate's insistence. This Shinto ritual had been in abeyance for over a century, and is performed only once by the emperor in the period of the enthronement ceremonies.

Higashiyama is among those enshrined in the Imperial mausoleum, Tsuki no wa no misasagi, at Sennyū-ji in Higashiyama-ku, Kyoto. Also enshrined in this location are this emperor's immediate Imperial predecessors since Emperor Go-Mizunoo – Meishō, Go-Kōmyō, Go-Sai and Reigen. Higashiyama's immediate Imperial successors, including Nakamikado, Sakuramachi, Momozono, Go-Sakuramachi and Go-Momozono, are enshrined here as well.

The years of Higashiyama's reign are more specifically identified by more than one era name or nengō.

Higashiyama's family included at least 11 children.

Higashiyama appears under the name of Tomohito in the novel The Samurai's Wife by author Laura Joh Rowland. In the novel, detective Sano Ichiro is sent to investigate the murder of an important official in the Imperial Court. Tomohito is labelled as a suspect, and is portrayed as a childish oaf at the start of the novel. He is later revealed to be the instigator behind a coming revolution against the Tokugawa regime, so he can seize control of Japan himself. However, his plan fails, and he is once again placed in the Imperial Palace, where he seems to have accepted his fate to never leave the palace.