Which opera, if any,  Venus and Adonis or Bluebeard's Castle has more acts ?
Venus and Adonis (opera) Venus and Adonis is an opera in three acts and a prologue by the English Baroque composer John Blow, composed in about 1683. It was written for the court of King Charles II at either London or Windsor. It is considered by some to be either a semi-opera or a masque, but "The New Grove" names it as the earliest known English opera.
Der Waffenschmied Der Waffenschmied (The Armourer) is an opera (Singspiel) in three acts by Albert Lortzing. The German-language libretto was by the composer after Friedrich Wilheim von Ziegler's "Liebhaber und Nebenbuhler in einer Person" (Lover and Rival in One Person). This is often considered his third most popular work. His works are considered to be part of the Biedermeier period. It premiered in Vienna at the Theater an der Wien on 31 May 1846 conducted by Lortzing. The role of Marie was written with Jenny Lind in mind who he hoped would sing the part. The opera was eventually successful enough that Lortzing was offered the post of Kapellmeister at the theatre which he held until the revolution of 1848, when he had to return to Leipzig. Arnold Schönberg, arranged Lortzing’s "Waffenschmied“ for piano for 4 hands. The story is set in the city of Worms in the 16th century.