The String Harmony

An online riddle, and a journey to everything

Other Levels

This page introduces optional levels other than the 50 main levels in the game. They are most likely not related to the main levels, and they are not required for the Hall of Fame. However, they are usually quite challenging, so you should gain sufficient experience from the main levels before attempting them.

This page will be updated irregularly. Stay tuned!

Forbidden Area

The Forbidden Area features 9 levels with style distinct from the main levels. They are unconventional levels using special tricks and/or topics. To access them, you need to apply the following hint:

"Unknown signals detected in forbidden area, which can be accessed only by entering quantum tunnel."

to a certain main level. Join the Discord server for more information.


Metapuzzles are long puzzles with many related sublevels. They are irregularly made when there are special events such as anniversaries. They do not require main levels and can be directly accessed from below: