Composed at the commission of Yoshiko Shibuya. It was premiered at her recital and dedicated to her.

Consisting of four movements, each movement possesses the character of a clownish transformation story. Therefore, the fundamental tone of this piece lies in a light, bright, and playful spirit.

First Movement

For subtle nuances leading to immense musical changes. The first half begins with the sounds of CAGE subtly emerging, and the movement concludes with sounds scattering like popping popcorn, ending on the four notes of BACH. The names of two composers are present here.

Second Movement

The Second Movement can be performed as a standalone piece titled "Daytime Annotation." The transformation structure of this movement spans from a musical idea like flowing clouds to the formation of a clear metrical structure. This single movement balances the other movements.

Third Movement

Inductive transformation to the quoted archetype. It is performed with the same feeling as playing the original piece from the beginning, but more exaggeratedly and at a slightly slower tempo. It is a bite-sized dessert movement with an atmosphere like "...and then the spell was broken, and he transformed into a beautiful prince..."

Fourth Movement

The Fourth Movement is a fast finale movement whose character changes like an amoeba. Nevertheless, as an allusion that this piece is merely an event within a birdcage (a metaphor for a limited framework), the four notes of CAGE are presented in the bass, and the notes B and D are drawn from 'Bird' at the end of the piece. One may also imagine Sun Wukong (the Monkey King) rampaging in the palm of Buddha.

When this piece is performed in the order of the First, Fourth, and Third Movements, it becomes a piece titled "Metamorphosis in a Birdcage 2."

Total duration: just under 15 minutes.