Long ago, at the time of the Later Han Dynasty in China (947–951), there was a boy named Tenko. When his mother was pregnant, she dreamt of a drum falling from the sky. The baby was then given the name Tenko (lit. ‘Heavenly Drum’). After he was born, a drum really fell from the sky, and Tenko could play beautiful music with it. Soon the fame of this instrument reached the Emperor, who ordered that it be brought to him. Tenko tried to run away with the drum but the Emperor’s guards caught him and drowned him in the Rosui River. However, when the drum was finally brought to the Emperor, no one could make a sound out of it. The Emperor then ordered Tenko’s father, Ōhaku, to come to palace and strike the drum.
Here begins the narration of the play. An Imperial Envoy visits Ōhaku, who is grieving the loss of his son. The Envoyee brings Ōhaku to the Emperor’s palace. There, Ōhaku laments the attachment of a father to his son, but the Envoyee urges him to strike the drum. As Ōhaku does so, a beautiful sound echoes in the hall. Moved by this miraculous event, the Emperor gifts Ōhaku with the drum. A Servant escorts Ōhaku home.
The Emperor orders that a memorial ceremony with orchestral music be performed in the memory of Tenko on the banks of the Rosui River. As the music begins Tenko’s Ghost appears. He is grateful for the ritual that has been held in his memory, and dances to the music of the orchestra. Tenko plays with the river water and strikes the drum, before disappearing with the dawn lights.
The first half of the play centres on the unjust death brought upon Tenko by the Emperor. Grief-stricken, Ōhaku has no power to voice his complaint against the sovereign. Instead, he blames the attachment between father and the son as the origin of his pain. In addition, the Emperor orders Ōhaku to strike Tenko’s drum, the only reminder of his beloved sign. However, as he strikes the drum, a beautiful sound is heard. The lyrics do not describe Ōhaku’s reaction to this miraculous event, yet the audience may imagine his surprise and deep emotion.
In contrast to the sadness of the first half, the second half of the play is filled with a festive atmosphere for the reunion between the father and the spirit of his son. Tenko performs the “gaku”, an instrumental dance that, in the noh repertory, is associated with Chinese characters. This dance begins slowly, but the tempo gradually increases. The numerous foot stamping sequences contribute to the playful atmosphere of the dance.
The theme of musical instruments, or other items, such as masks, falling from the heavens and later treasured as magical items can be found in narratives around the world.
In the performance variant named Rōko-no-mai, the entrance section for the character of Ōhaku is cut, and the dance of Tenko is different from the standard version: the taiko stick drum also joins the orchestra, the flute plays a higher pitch, and the main character performs movements suggesting that Tenko is playing with the river water.