Here's why:
* Pokemon Shiny Gold is a fan-made game: It is a ROM hack based on Pokemon Gold and Silver. The developers added new features and content, but they didn't include HM01 CUT.
* The game's mechanics are different: The game mechanics are based on the original Pokemon Gold and Silver, and CUT is not a move that was available in those games.
What to do instead:
If you're looking for a move that can break down obstacles in Pokemon Shiny Gold, you can use the following:
* HM02 Flash: This will allow you to see in dark areas and can be used to find hidden paths.
* Rock Smash: This is a TM, and it can be used to break rocks.
If you want to play a Pokemon game that has HM01 CUT, you'll need to try a different game, such as Pokemon FireRed, LeafGreen, or Emerald.