Glossary: HM (Hidden Machine)

An HM, short for Hidden Machine, is a reusable item that can be used to teach your Pokémon moves that can be used in the overworld after earning the necessary Badge. These are typically required in order to progress in the main series games where they are present in, although they are removed in the Alola and Galar region games, or in Let’s Go, Pikachu & Eevee.

Unlike most moves, HM moves cannot be forgotten or replaced with other moves; once they’re taught to a Pokémon, the Pokémon is stuck with the move unless they are taken to the Move Deleter NPC (which is not even available in Generation I).

All HM Moves

Below, you’ll find information about all of the different HM moves in the Pokémon games. Some of these have become TM moves after they were first introduced, so not all of them are still HM moves. You can find a list of the HMs in each game further down.

In any game where these are HMs, they can be used outside of battle by selecting the Pokémon from the party screen and choosing the move from the options. The effect varies by HM and even by game.

Cut

Cut is one of the earliest HMs most games give you. It gives you the ability to cut down small trees that often times block your path or block optional areas leading to items or other features.

Cut is usually required for progression early on, but generally is only used for optional areas after its first few uses. It is a fairly weak Physical-based Normal-type move that has no additional effect in battle; as such, it is not a good move to teach to any of your main Pokémon, and it is best to teach it to an “HM Buddy” that you won’t be using in battle.

In some games, such as Generation I and II games, Cut can be used on the field to chop up a 2×2 patch of tall grass nearby. This is temporary and the tall grass will regrow after leaving the area, but it can be used to clear a path where you won’t have to fight wild Pokémon, although the time investment of having to go into the menu to use it every few steps make it inefficient.

Cut appears in the following games as an HM:

Flash

Flash is another HM move that’s available fairly early on in games that it’s in. It is an HM in Generation I–III and is a TM in all later games, although regardless of whether it is an HM or TM, it can be used outside of battle in Generation I–VI to produce the same effect, with the only difference being it has no Badge requirement if it is a TM in a game.

When used in battle, it lowers the foe’s accuracy by one stage. As such, it is a pretty underwhelming move to use in battle and should be used only on an “HM Buddy” to avoid wasting a move slot on one of your more useful Pokémon.

It can be used outside of battle while in a particularly dark area, such as certain caves like the Rock Tunnel or the basement of the Granite Cave, to temporarily illuminate the area and make it easier to see. Not every cave requires Flash; in fact, few actually do.

In some games, you aren’t able to see anything in the cave or dark area until you use Flash, but some other games make it a little less important as you can see a few spaces around you even without using Flash.

Although Flash is recommended for traversing caves and similarly dark areas, it is completely possible to navigate any cave or dark area without the use of Flash, especially for players that are familiar with the area or are using a map.

Flash appears as an HM in the following games:

Fly

Fly is a fairly useful HM move that isn’t actually required and is usually available around the middle of the game. Its use is more practical than all other HMs, giving the player the ability to return to any previously visited Pokémon Center, and it can be used as long as the user isn’t inside of a cave, building, or other dwelling. This makes getting around the region substantially faster than without using Fly.

Because Fly isn’t required to clear any puzzles or progress in the game, if you don’t want to use a move slot for Fly, it’s fairly easy to just keep a Pokémon with Fly in the PC and withdraw that when you need to quickly travel.

As for its use in battle, Fly isn’t great, but—thankfully—it’s not that bad, either. It’s a reasonably strong Physical-based Flying-type move that takes two turns to use, with the first turn putting the user into a state of invulnerability where it can’t be hit or affected by most moves, and then the second turn actually doing the damage. Against other human players, this is extremely easy to play around, but for in-game purposes, such as progressing through the game, it’s usually fine enough as the opponents don’t use set up moves too often.

One other downside to Fly as a move is that it does not have 100% accuracy, meaning you’ll miss every now and then. Because of that, moves like Drill Peck are almost always preferred, and oftentimes players would rather just use a more reliable, single-turn move like Aerial Ace or Wing Attack instead of spending two turns on Fly.

Again, thankfully, it’s not bad and it’s one of those HM moves that you can usually justify having on your team, especially given how convenient being able to quickly travel anywhere is.

Strength

Strength is a fairly straightforward HM move, both inside and outside of battle. When used outside of battle, it grants the player the ability to move boulders around. This is necessary to solve many puzzles or gain access to several optional items or areas.

In Generation I, you have to use Strength from the Pokémon menu (after selecting a Pokémon, e.g. to view its stats) to activate it; in later Generations, you can press A next to a boulder that can be moved and it will allow you to activate Strength from there without having to go into the menu. The Strength “effect” lasts until you leave the room or area, including moving to a different floor, so you’ll have to renew the effect for dungeons that have multiple floors or rooms.

In Kanto, Johto, Hoenn, and Sinnoh, the boulders that can be moved with Strength are fairly small, taking up one tile, essentially making them the same size as the player. After activating Strength, they can be pushed forward by standing in front of the boulder and moving in that direction. If a boulder is pushed against a wall, it cannot be moved away from that wall, and if it is pushed into a corner, it is stuck there until the player leaves the room. Because of this, it’s important to be careful when pushing boulders to avoid getting them into a position where they can’t be moved.

Sometimes these boulders need to be pushed onto switches or down into holes. If the boulders are pushed onto switches or down holes, they will not reappear when the player leaves the room, as they have reached their destination.

In Unova and Kalos, boulders are much larger than the player, taking up a 2×2 tile space. They can still be pushed, but they are now usually pushed into holes that can be crossed after the boulders have fallen into them, leading the way to new areas or optional items. These are often used to create shortcuts in these regions, allowing the player to cross the sunken boulder to get back to a later portion of the dungeon, since they can be pushed from only one side.

Once a boulder has been pushed into a hole, it is stuck there permanently, which is always a good thing in this case as all Strength “puzzles” are designed to have any holes as destinations for the boulders and you’ll only need to reset it if you mess the puzzle up.

As for a move to use inside of battle, Strength is fairly mediocre, but, like Fly, it’s not bad. It’s just not good. It is always an 80 power Physical-based Normal-type move that has no additional effects. 80 power is reasonable, although in any game where Return is easy to obtain, Return almost always ends up being a better choice due to it having 102 power at max happiness; in games where it isn’t, though, or is a pain to get multiple copies of, Strength is fine and is particularly good on Normal-type Pokémon due to it benefiting from STAB. Since it’s a Normal-type move, it won’t ever be super effective against anything, so that’s why it’s not as good on non-Normal-type Pokémon.

Surf

Surf is a particularly useful HM move as it enables you to cross water, lakes, and rivers, allowing access to new areas, items, and more. Gaining access to Surf usually grants access to a lot of different possibilities and areas to explore, so it’s a very good HM to have for exploration. You can press the A button when facing the water to activate Surf, if you have a Pokémon with Surf in your party and the necessary Badge.

While most HMs are bad and a few are “OK,” Surf is one of the few HM moves that is downright good to use in battle. It is a very strong 90-95 power Special-based Water-type move with no extra effects, and it hits all other Pokémon when used in a Double Battle (just the enemy Pokémon in Generation III) or Horde Battle, and all adjacent Pokémon in a Triple Battle. This can sometimes make it a bit of a hindrance when being used in Double Battles, but other than that, it is an exceptional move and a staple for most Water-type Pokémon.

Because of this, it’s almost never a problem including Surf on any of your main Pokémon’s moves and an HM Buddy is not usually necessary for this move.

Surf is also a prerequisite for a few other water-themed HM moves, namely Whirlpool and Waterfall, which require you to be surfing in order to use them.

In any Generation VI game, if you use Surf on a Lapras, you’ll actually be shown riding the Lapras instead of the generic surfing sprite. Additionally, in Pokémon Omega Ruby and Alpha Sapphire, you can Surf on Wailmer to ride it instead, or you can use Surf on Kyogre to go even faster, or lastly you can use Surf on Sharpedo to go incredibly fast.

Whirlpool

Introduced in Generation II, Whirlpool is a very underwhelming HM move that is only used to clear a whirlpool on the overworld, allowing you to cross it. These whirlpools usually block entrance to an area, and oftentimes these areas are necessary in order to progress through the game.

Due to how few areas actually have a whirlpool that requires Whirlpool to cross, and due to the fact that Whirlpool is a very bad move when used in battle, it’s not a good move to teach any of your main Pokémon and should really be relegated to an HM Buddy. It has extremely low power and traps the target for a few turns, preventing it from switching out, similar to Wrap or Fire Spin.

Waterfall

Introduced in Generation II, Waterfall is an HM move that enables the user to climb waterfalls outside of battle, granting access to optional areas or items. Waterfalls also usually block the way to the Pokémon League, so being able to use Waterfall is important for progressing to the end of the game. As such, this is typically one of the last HM moves you’ll gain access to.

Waterfall is similar to Surf in the fact that it’s one of those rare good HM moves. While not quite as good as Surf, it is a very solid 80 power Physical-based Water-type move, and it even has a chance of making the foe flinch starting in Generation IV. It isn’t multi-target like Surf is and is a few points weaker, but it’s a Physical option as opposed to a Special-based one like Surf is, making it a much better choice for Water-type Pokémon with a good Attack stat.

Because of this, Waterfall is not usually something you’ll need to put on an HM Buddy. However, the problem lies with the fact that there aren’t a lot of areas that require Waterfall (unlike Surf), and if you already have a Pokémon with Surf, it’s rather redundant to give the same Pokémon both Surf and Waterfall, especially if the Pokémon has a higher or even roughly equivalent Special Attack stat compared to its Attack stat.

If you have a Pokémon that can make use of Waterfall’s Physical category, then by all means, go with Waterfall, but if your only option is to put it on your only Water-type Pokémon, the one that’s already using Surf, and its Attack stat isn’t anything to write home about, then you would probably be better off just putting it on an HM Buddy and only pulling that HM Buddy out when you need it.

Rock Smash

Although Rock Smash was introduced in Generation II as a move that could be used outside of battle, it was upgraded to HM status in Generation III, where it was required to progress through the game. In games where it’s an HM, it’s usually available fairly early in the game.

When used outside of battle (whether as an HM or not), the Pokémon with Rock Smash has the power to smash small, cracked rocks that are scattered around the world. Rocks that can be smashed with Rock Smash appear visually different than other, non-smashable rocks, usually with a different color hue. When using Rock Smash in this way, the rock being smashed can sometimes hide a wild Pokémon, or sometimes items can be found where the rock was instead. This behavior varies a bit by game, though.

Inside of battle, though, Rock Smash is a rather underwhelming Physical-based Fighting-type move—in fact, in Generation III (and prior), it’s downright awful, having only a 20 power in those games. It got bumped up to 40 power in Generation IV, and in all games it has a 50% chance of lowering the target’s Defense by one stage. A 40 power Fighting-type move can be OK early on in the game, and it often comes at a time where having access to a Fighting-type move of any sort helps. It’s also learnable by many non-Fighting-type Pokémon. But it’s just 40 power (or 20 in earlier games), so it will quickly become lackluster, and you’ll be unable to remove it without the Move Deleter.

Because of this, Rock Smash is usually best taught to an HM Buddy rather than a main Pokémon on your team.

Dive

Dive is an HM move that was introduced in Generation III and brought back as an HM move for Generation V as well (in addition to being present in Omega Ruby and Alpha Sapphire from Generation VI). It is used outside of battle to dive beneath the water, granting access to the seafloor or other sunken areas.

As Dive can only be used while on the water, a Pokémon with Surf is a prerequisite before using Dive. You can’t dive beneath all of the water—only patches of water that look particularly dark can be dove down into with Dive.

In doing so in the Hoenn games, you’ll reach the seafloor or underwater portions of the eastern routes, which have deep sea encounters, some items, and grant access to certain areas inaccessible from the surface, such as the Seafloor Cavern and the entrance to Sootopolis City.

In the Unova games, Dive is entirely optional, but grants access to a few items here and there and also allows you to reach the Abyssal Ruins in Undella Bay. It’s far less useful in these games than in the Hoenn games.

As for its performance inside of battle, it’s very similar to Fly, meaning you spend a turn where you can’t be hit by most moves, and then you attack on the second turn. It’s an 80 power Physical-based Water-type move, but since Waterfall (or Surf, for a Special-based move) is available in any game where Dive is available, it’s definitely not a good move to teach any of your main Pokémon. Definitely put this on an HM Buddy unless there’s no way around it, especially because there are very few areas you’ll even need to use it.

Defog

Defog is an HM move only in the Sinnoh games—Diamond, Pearl, and Platinum. When used outside of battle, it lifts any thick fog in the nearby area. While you can traverse foggy areas, it’s hard to see clearly without using Defog, and the thick fog also affects all Pokémon’s ability to hit their targets with moves, reducing their accuracy while it’s foggy.

There are only a few areas in the region that are foggy, so it’s not necessary to bring along on any of your main Pokémon and is best put onto an HM Buddy like anything in the Zubat line.

While used in battle in Generation IV–V, it lowers the target’s evasion by one stage and removes effects like Light Screen, Reflect, or Safeguard on the foe’s side of the field, in addition to any Spikes, Toxic Spikes, or Stealth Rocks you’ve set down on their field. In Generation VI and on, though, it also clears any Spikes, Toxic Spikes, or Stealth Rocks affecting your side of the field, making it substantially more useful, especially in player-vs-player fights.

For standard in-game purposes (such as beating the game), though, it’s an awful move to use in battle, so it should definitely be put onto an HM Buddy and not any Pokémon on your main team. The only good news is that you gain access to the Move Deleter shortly after getting access to Defog, so at least you can get rid of it shortly afterwards.

Rock Climb

Also introduced in Generation IV, but ultimately retired as an HM move after that Generation, Rock Climb does exactly what the name suggests—it allows you to climb rocks. Specifically, you can climb rocky walls, but not any walls—there need to be small little notches on the walls you wish to climb. Visually, these notches vaguely resemble footprints.

There are oftentimes optional items or Trainers waiting atop climbable rocks. In the Sinnoh region, Rock Climb is also necessary in order to progress through the game, and you get the ability to use Rock Climb outside of battle after defeating the 7th Gym Leader in Snowpoint City.

While the original Gold, Silver, and Crystal didn’t have Rock Climb, in HeartGold and SoulSilver, Rock Climb is an HM available after you’ve beaten the Kanto Gym Leaders and allows access to a few optional areas for some items.

When used in battle, Rock Climb is mediocre and, once again, should be put onto an HM Buddy like Bibarel (in Sinnoh). It is a Physical-based Normal-type move that has a chance of confusing the target, but it also has only 90% accuracy, which is just not reliable when compared to other Normal-type moves like Return or even Strength.

More About HMs

“HM Buddy”

Although some HM moves are quite good, such as Surf, most HM moves are lackluster in their battle capabilities, especially early-game HM moves like Cut or Rock Smash, so care must be considered when using HMs on Pokémon.

This can be alleviated by having a dedicated “HM Buddy,” such as Bidoof or Bibarel, that is used for the sole purpose of carrying HM moves, especially the bad ones. The HM Buddy isn’t generally used in battle and its primary purpose is to use HM moves, leaving you free to use your choice of moves on the rest of your team without needing to worry about HM moves.

One downside to this approach is that each HM Buddy takes up space in your party, which can only consist of six Pokémon at most.

Move Deleter

Starting in Generation II, HM moves can be removed thanks to an NPC known as the Move Deleter, who can remove whichever move the player chooses from a Pokémon, including HM moves. Since HM moves cannot be removed in any other means, this is a helpful way to recover a move slot if you had to teach one of your main Pokémon an underwhelming HM move like Cut, which isn’t usually required to progress anywhere later on in the game.

The Move Deleter’s services are always free, regardless of which game you’re playing.

Here’s where you can find the Move Deleter in each region, along with how many Badges are usually required to get to that point (for a point of reference):

• Kanto region: Fuchsia City (4–5 Badges)
  • This is only available in FireRed and LeafGreen, as it is not available in Generation I and the games that start in the Johto region have their Move Deleter in Blackthorn City instead.
• Johto region: Blackthorn City (7 Badges)
• Hoenn region: Lilycove City (6 Badges)
• Sinnoh region: Canalave City (5 Badges)
• Unova region: Mistralton City (5 Badges)
• Kalos region: Dendemille Town (6 Badges)
• Alola region*: Hau’oli City Pokémon Center (beginning of the game)
• Galar region*: Any Pokémon Center

* HMs do not exist in these regions, although there is still a Move Deleter to delete unwanted moves.

Transferring HM Moves

In order to transfer Pokémon from one Generation to another Generation—from Generation III and beyond, that is—you have to use certain methods that depend on the current and target Generation. Some of these methods, such as using the Pal Park to transfer Pokémon from Generation III games to Generation IV, require any HM moves on the Pokémon you wish to be transferred be deleted first by using the Move Deleter. This is presumably to prevent the player from getting stuck in the older game if they no longer have a Pokémon that can use HM moves.

In Generation VI, Pokémon with HM moves can be placed into Pokémon Bank just fine and then subsequently transferred to Generation VII and beyond, although Pokémon in your party cannot be placed into Pokémon Bank and must first be put into the PC, preventing you from getting stuck somewhere.

Since Generation VI games allow you to trade anywhere by using the PSS, you cannot trade Pokémon from your party if it knows an HM move—you can deposit it to the PC, though, and trade it.

Releasing Pokémon with HM Moves

You’re generally able to release Pokémon that know HM moves without any issue. However, in Generation III and IV, if you try to release a Pokémon with a required HM move and it’s the last Pokémon in either your party or your PC with that move, instead of releasing the Pokémon, a message will appear indicating that the Pokémon has returned to the player.