ELI5: Explain Like I'm 5

Zaikyō kī kyoku

Zaikyō kī kyoku is a phrase in Japanese that means "default tune". A tune is a special kind of sound that is made up of different musical notes played in a particular order.

Imagine you have a toy keyboard that you can press different keys on to make different sounds. Every time you turn on the keyboard, it starts playing a specific tune by default, which means you don't have to pick a tune or press any keys. This default tune is zaikyō kī kyoku in Japanese.

In simpler terms, it's like when you turn on your favorite toy or game, and it automatically starts doing something without you having to do anything. The default tune is like that for a musical keyboard.