Act I Courtyard of Ko-Ko's Official Residence Gentlemen of the Japanese town of Titipu are gathered (""If you want to know who we are""). A wandering musician, Nanki-Poo, enters and introduces himself (""A wand'ring minstrel I""). He inquires about his beloved, the maiden Yum-Yum, a ward of Ko-Ko (formerly a cheap tailor). One of the gentlemen, Pish-Tush, explains that when the Mikado decreed that flirting was a capital crime, the Titipu authorities frustrated the decree by appointing Ko-Ko, a prisoner condemned to death for flirting, to the post of Lord High Executioner (""Our great Mikado, virtuous man""). Ko-Ko was ""next"" to be decapitated, and the Titipu authorities reasoned that he could ""not cut off another's head until he cut his own off"", and since Ko-Ko was not likely to try to execute himself, no executions could take place. However, all officials but the haughty Pooh-Bah proved too proud to serve under an ex-tailor, and Pooh-Bah now holds all their posts—and collects all their salaries. Pooh-Bah informs Nanki-Poo that Yum-Yum is scheduled to marry Ko-Ko on that very day (""Young man, despair""). Ko-Ko – 1926 costume design by Charles Ricketts Ko-Ko enters (""Behold the Lord High Executioner""), and asserts himself by reading off a list of people ""who would not be missed"" if they were executed (""As some day it may happen""). Soon, Yum-Yum appears with two of her friends (sometimes referred to as her ""sisters""), Peep-Bo and Pitti-Sing (""Comes a train of little ladies"", ""Three little maids from school""). Ko-Ko encourages a respectful greeting between Pooh-Bah and the young girls, but Pooh-Bah will have none of it (""So please you, sir""). Nanki-Poo arrives on the scene and informs Ko-Ko of his love for Yum-Yum. Ko-Ko sends him away, but Nanki-Poo manages to meet with his beloved and reveals his secret to Yum-Yum—he is the son and heir of the Mikado, but he's travelling in disguise to avoid the amorous advances of Katisha, an elderly lady of his father's court. They lament over what the law forbids them to do (""Were you not to Ko-Ko plighted""). Ko-Ko receives news that the Mikado has decreed that unless an execution is carried out within a month, the town will be reduced to the rank of a village—which would bring ""irretrievable ruin"". Pooh-Bah and Pish-Tush point to Ko-Ko himself as the obvious choice for beheading, since he was already under sentence of death (""I am so proud""), but Ko-Ko protests that, firstly, it would be ""extremely difficult, not to say dangerous"", for him to attempt to execute himself, and secondly, it would be suicide, which is a ""capital offence"". Fortuitously, Ko-Ko discovers that Nanki-Poo, in despair over losing Yum-Yum, is preparing to commit suicide. After ascertaining that nothing would change Nanki-Poo's mind, Ko-Ko makes a bargain with him: Nanki-Poo may marry Yum-Yum for one month if, at the end of that time, he allows himself to be executed. Ko-Ko would then marry the young widow. Everyone arrives to celebrate Nanki-Poo and Yum-Yum's union (""With aspect stern and gloomy stride""), but the festivities are interrupted by the arrival of Katisha, who has come to claim Nanki-Poo as her husband. However, the townspeople are much more sympathetic to the young couple, and her attempts to reveal Nanki-Poo's secret are drowned out by the shouting of the crowd. Outwitted but not defeated, Katisha makes it clear that she intends to return.