The query appears to refer to (Opus 1) by Johann Christian Bach , a collection of six harpsichord or piano concertos published in 1763 (often cited alongside his other major early works like Opp. 7 and 13). The Story of Johann Christian Bach's Opp. 1
Johann Christian Bach, the youngest son of the legendary Johann Sebastian Bach, was known as the "London Bach". After studying in Italy, he moved to London in 1762 and quickly became a central figure in the city's musical life. blank 1 opp 2012 skachat
In other technical and scientific contexts, "blank 1" and "OPP" may refer to different items: The query appears to refer to (Opus 1)