The Mikado  or The Town of Titipu is a comic opera in two acts featuring the music of Arthur Sullivan and libretto by W.S. Gilbert.   It was the ninth of the 14 operatic collaborations by these two gentlemen  and opened on March 14, 1885 in London.  The Mikado  remains the most frequently performed Savoy Operas.

An old 1960s version of Mikado may be seen here:

https://www.youtube.com/watch?v=c_DlC4n9CFQ