Hidden Machines (HMs) in Red/Blue/Yellow
As the first Pokémon games, Red/Blue introduce 5 Hidden Machines that are used in order to progress through the game. Pokémon Yellow keeps everything the same. In Generation 1, HM moves cannot be deleted once learned.
The Pokémon can be filtered by ticking the checkboxes. This is useful for deciding on an
HM Slave - a Pokémon knowing only HM moves, to save all four spots for good moves on other Pokémon.
Where to find the HMs in Red/Blue/Yellow.
Pokémon HM chart