Prelude 1 Allegretto (1960) Prelude 2 Andante (1961) Prelude 3 Allegro con spirito (1961) Prelude 4 Largetto (1960) Prelude 5 Allegro (1961)

Written between 1960 and 1961, the year after Sato won the Japan Music Competition, and published in 1962. It was published by Kawai Gakufu in 1965. At this time, the composer was creating under the strong influence of his teacher, Yasuji Kiyose. According to the commentary in the score, the work was created with the challenge of "not merely being confined to Japanese materials, but rather how to develop Japanese tradition in the modern era." In other words, he was likely confronting the challenge of how to form his own individuality while utilizing what he had learned from Kiyose. In later years, Sato explained the characteristics of his teacher's works from various angles in an article titled "Yasuji Kiyose's Musical Idiom," published in Ensemble magazine, Issue 72 (released October 1972). The tendencies mentioned there, such as "Kiyose-style pentatonic scale that is not a pure pentatonic scale," "preference for augmented intervals," "avoidance of clear dominant progressions," and "preference for ostinato," generally apply to this work, but the slight deviations reveal the nascent individuality unique to Sato.

• Prelude 1: While having B-flat as its tonic, this piece is constructed using a ritsu scale (a type of pentatonic scale) that omits the third (D) and leading tone (A), not only in the melody but also in other parts (except for measures 17-20, which introduce harmonic variations).
• Prelude 2: This piece is likely a work influenced by Debussy's Hommage à Rameau; its tonic is F, but it avoids the third of the tonic chord.
• Prelude 3: Several ostinatos are connected in a block-like fashion. Although there are sections that sound like a middle section, the same melodic patterns as the main section are used there, indicating an ingenuity to avoid a simple ternary form.
• Prelude 4: This piece features a melody based on a folk scale with C-sharp as its tonic, developing contrapuntally by increasing voices from single line, to unison, then to two and three voices.
• Prelude 5: This is a perpetuum mobile toccata beginning in E-flat minor. The theme with triplets and dotted rhythms, appearing over a drone in the middle section, reappears in the coda, bringing the piece to a powerful close.