Kingdom of Paradise, released as Tenchi no Mon (天地の門) in Japan and Key of Heaven in Europe, is an action role-playing video game developed by Climax Entertainment and published by Sony Computer Entertainment for the PlayStation Portable.

Heavily influenced by Asian culture in general, and Chinese Wuxia fantasy in particular, the game contains clans named after the Ssu Ling.

The story of this game takes place in an almost feudal China, which is simulated through the fictitious world of Ouka.

The continent of Ouka is separated into five divisions: Northern (Genbu), Eastern (Seiryu), Southern (Suzaku) Western (Byakko) and Central (Kirin).

Three hundred years previously there is said to have been the Seima-Ouka war, in which the Clan Lords of Ouka prevailed.

However, nobody was alive three hundred years ago to recount the mysterious events of the war – except the Kirin Lord Gikyo and the Seiman twins, Lu Yan and Li Yin (who are over three hundred years old but look deceptively young in the game because they "are able to sustain [them]selves on the chi of the yin and yang moons" as told by Gikyo.

The Forbidden Poem, written by Lu Yan and Li Yin, speaks of the war, reading: Five great gates of Ouka be, Name them here for all to see; Seiryu, Byakko and Genbu Kirin and Suzaku be there too; At Heaven’s gate twin keys you need; At Earth’s gates, bows the Divine Steed; The soul is born as the Yang moon whirls The body is born as the Yin moon twirls The twin moons make a mighty hum

The surviving disciple named Sui Lin tracks down Shinbu to tell him that their clan was destroyed, and they're the only two survivors.

Shinbu also uses a form of magic called Chi Arts which the player learns from a sacred stone in each clan's temple, and uses it in battle.

The player holds down the square button to charge chi and presses it again to use it, usually causing large amounts of damage.