HM

A Hidden Machine (Japanese: ひでんマシン Secret Machine), HM for short, is an item that, like a TM, is used to teach a Pokémon a move. HMs can be used an unlimited number of times and cannot be disposed of. Moves taught by HMs, known as HM moves or hidden movesFormatted as "hidden move" from Generation III to Generation V, "Hidden Move" in and , and "<sc>Hidden</sc> move" (Japanese: ひでんわざ secret move; formatted in kanji as secret move only at the Entralink and when using Poké Transfer in Generation V) in FireRed and LeafGreen., cannot normally be forgotten. These moves have a use as field moves in games in which they are HMs.
In Japanese games, it is said that HMs are Key Items, according to the text that appears when the player attempts to delete them. However, this was lost in the localization, where it is simply said that some items are too important to be deleted.
Starting in Generation VII, there are no longer any HMs. Some former HM moves are instead TM or TR moves in these games. The field move uses of HM moves are replaced by:
* Poké Ride
* Secret Techniques
* Flying Taxi and Rotom Bike
* Pokétch (Hidden Moves app)
* 
* Flying Taxi and /'s upgraded abilities
==In the core series==
===Mechanics===
HMs can be used any number of times, and cannot be tossed, sold, or held. This contrasts to TMs in Generations to , in which TMs are single-use items that can be tossed, sold, or held. In , HMs cannot be stored in a PC.
Moves taught by HMs are all field moves in the games in which they are HMs, but some field moves are not HM moves. Like all field moves, they can be used outside of battle even if the Pokémon has fainted or no PP in that move (using it as a field move does not consume PP). Except for Generation V, the player can only use HM moves as field moves if they have the appropriate Badge or number of Badges (the exact requirements vary between games).
HM moves cannot be forgotten by Pokémon under normal circumstances in the games in which they are HMs, even if they are not learned via HM. They can be deleted by the Move Deleter, although cannot be deleted in if the Pokémon is the only one in the player's party or PC that knows the move. If a Pokémon learns a new move while in Pokémon Day Care, an HM move can be replaced if it is at the top of the list; however, in Generation I, the Pokémon Day Care will not accept Pokémon that know HM moves.
In Generation III and IV, a Pokémon knowing an HM move cannot be transferred to the next generation unless the HM move is removed (e.g. via Move Deleter). In Generation III, prevents sending forward from despite not being considered an HM by those games; in Generation IV, since Dive is no longer an HM move, Pokémon with Dive can freely be sent into Generation V games. In Generation IV, and only prevent Pokémon being sent forward from the games they are an HM in (e.g. a Pokémon knowing Whirlpool can be sent from Pokémon Platinum to Generation V); since Whirlpool is not an HM move in Generation III, Pokémon with Whirlpool can freely be sent into from Generation III.
Unlike in previous inter-generational transfers, Pokémon transferred from Generation I or V via Poké Transporter that know HM moves do not require these moves to be deleted. Pokémon which know HM moves cannot be traded over Nintendo Wi-Fi Connection or the Nintendo Network, and also cannot be deposited in the GTS. Pokémon that know HM moves can also be freely deposited and withdrawn from Pokémon Bank.
In Generation V, Pokémon knowing an HM move cannot be traded via infrared communications if they are in the player's party, to prevent a player from potentially becoming stuck somewhere that requires an HM move to escape.
In Generation III and IV, if the player attempts to release a Pokémon that is the only Pokémon in their party or PC that knows a certain HM move, it will immediately return. In Generation III, these moves are and . In Generation IV, they are Surf, , and , as well as in .
===HMs by generation===
====Generation I====
Five HM moves were introduced in this generation. Three HMs (, , and ) are required for completing the games. 
HM	Move	Location found	Badge required
 	 	S.S. Anne 	
 	 	 	
 	 	 	
 	 	Fuchsia City 	
 	 	 	
Four of them remain as HM moves even through Generation VI, while the fifth, , retains the ability to be used outside of battle (to light dark caves in Generation V, or reduce encounters with wild Pokémon in Generation VI).
None of these moves are able to be forgotten in Generation I, and a Pokémon with these moves cannot be raised by the Pokémon Day Care on . Unlike in later generations, all of these moves must be selected from the Pokémon screen to be used.
====Generation II====
The five HMs from Generation I return, while a new move, , is introduced as an HM, and an old move, , becomes one as well. Five HMs are required for completing the games: the same three from before (, , and ) and the two new HMs.
HM	Move	Location found 	Badge required
 	 	Ilex Forest 	
 	 	Cianwood City 	
 	 	Ecruteak City 	
 	 	Olivine City 	
 	 	Sprout Tower 	
 	 	Team Rocket'sHideout	
 	 	Ice Path 	
A Move Deleter was added to the games, mostly with the intention of making possible the ability to delete that a had learned in order to be able to trade it back, though with the side effect of HM moves now being able to be forgotten.
From this generation on, Pokémon with HM moves are allowed in the Day Care, and fathers with HM moves will pass the moves down to their children as they would a TM move. HM moves can also be used just by checking the obstacle that the HM will clear, such as able water or a movable rock.
====Generation III====
=====Hoenn=====
 lost its HM status, while gained HM status, and a new move, , became an HM, raising the total number to eight. Five HMs are required for completing the games: , , , , and . While Cut is not required anymore, it can still be used to access optional areas.
HM	Move	Location found 	Badge required
 	 	Rustboro City 	
 	 	 	
 	 	Petalburg City 	
 	 	Rusturf Tunnel 	
 	 	Granite Cave 	
 	 	Mauville City 	
 	 	Cave of Origin 	
 	 	Sootopolis City	
 	 	Mossdeep City 	
=====Kanto=====
In Kanto, due to a lack of use for outside of battle, HM08 is unobtainable and can only be accessed through cheating. The first five HMs can be acquired through the same methods as in Generation I, while HM06 and HM07 can be found in the Sevii Islands later in the game.
Three HMs are required for completing the games: the same ones from Generation I (, , and ). In addition, is required for finishing the Pokémon Network machine, which allows trading with the Hoenn games.
HM	Move	Location found	Badge required
 	 	S.S. Anne 	
 	 	 	
 	 	Safari Zone 	
 	 	Fuchsia City 	
 	 	 	
 	 	 	
 	 	Icefall Cave 	
====Generation IV====
=====Sinnoh=====
For the first time, one of the original HMs, Flash, lost its status to a new move, , while HM08 was brought back as .
Six HMs are required for completing the games: , , , , , and .
HM	Move	Location found	Badge required
 	 	Eterna City 	
 	 	Veilstone City	
 	 	Celestic Town 	
 	 	Celestic Town 	
 	 	Lost Tower 	
 	 	Iron Island 	
 	 	Great Marsh 	
 	 	Solaceon Ruins	
 	 	Oreburgh Gate 	
 	 	Sunyshore City	
 	 	 	
=====Johto and Kanto=====
Defog lost its HM status in Johto for the return of ; all other HMs retained their status from the prior Sinnoh games.
Six HMs are required for completing the games: , , , , , and .
HM	Move	Location found 	Badge required
 	 	Ilex Forest 	
 	 	Cianwood City 	
 	 	Ecruteak City 	
 	 	 	
 	 	Team Rocket HQ 	
 	 	 	
 	 	Ice Path 	
 	 	Professor Oak'sLaboratory	
====Generation V====
HMs were reduced to six in Generation V; HM07 and HM08 no longer exist in the coding of . Dive returns for use in Unova. This generation marks the first and only time that HM moves do not require Gym Badges for use outside of battle. Although most HM moves cannot be obtained before earning certain Gym Badges, if the player obtains a Pokémon that has learned an HM move through other means (via level-up, trading, etc.) the player will be able to use the HM in the field without restrictions.
When a move is replaced by an HM, the HM move takes on the current PP of the replaced move until healed or replenished. The same also applies for replacing old moves with TMs.
Of all the HMs, only a single use of is required at the Dreamyard for completing Pokémon Black and White. Only and are required for completing . Cut, Surf, , , and can still be often used to access optional areas. Strength may also often be optionally used to make shortcuts.
HM	Move	Location found	Location found
 	 	Striaton City 	Virbank City
 	 	Driftveil City	
 	 	Twist Mountain	
 	 	Nimbasa City 	Castelia Sewers
 	 	 	
 	 	Undella Town 	Undella Town
====Generation VI====
HMs have returned to requiring a Badge to use them.
When a move is replaced by an HM, the HM move takes on the current PP of the replaced move until healed or replenished. The same also applies for replacing old moves with TMs.
=====Kalos=====
HMs were reduced to five in Kalos like in Generation l. The HMs are the same as Generation V, except HM06 was removed.
 and are required to complete the game. , Surf, Strength, and can be often used to access optional areas. Strength may also often be optionally used to make shortcuts.
Though is not an HM, it can still be used outside of battle, unlike in Generation V.
HM	Move	Location found	Badge required
 	 	Parfum Palace 	
 	 	Coumarine City	
 	 	Shalour City 	
 	 	Cyllage City 	
 	 	 	
=====Hoenn=====
HMs were increased to seven in Hoenn. and regained their HM status.
Seven of the eight original Hoenn HMs are available in the remakes. is the exception, which is still usable outside of battle as usual, but is not an HM anymore since Generation IV.
Like in the original Hoenn games, five HMs are required for completing the games (, , , , and ), while Cut can be used to access optional areas.
HM	Move	Location found	Badge required
 	 	Rustboro City 	
 	 	 	
 	 	Petalburg City	
 	 	 	
 	 	Sootopolis Gym	
 	 	Mauville City 	
 	 	Mossdeep City 	
===HM-exclusive moves===
Due to the nature of HMs, these moves are often exclusively taught by them.
HM moves	Generation	Generation	Generation	Generation	Generation	Generation
HM moves	 	 	 	 	 	
 	✔ 	✔ 	✔ 	✔ 	✔ 	✔
 	✔ 	✔ 	 	 	 	
 	✔ 	✔ 	✔ 	✔ 	✔ 	✔
 	✔ 	✔ 	✔ 	✔ 	✔ 	✔
 	✔ 	✔ 	✔ 	 	 	
 	 	✔ 	 	 	 	
 	 	 	 	 	 	
 	 	 	✔ 	✔ 	 	
 	 	 	✔ 	 	 	
 	 	 	 	✔ 	 	
 	 	 	 	✔ 	 	
==In spin-off games==
===Pokémon Mystery Dungeon series===
Prior to , HMs can be used an infinite amount of times and are colored differently to TMs. HMs cannot be used inside dungeons and are more difficult to obtain than TMs. In Red Rescue Team and Blue Rescue Team, each HM can only be found once in specific dungeons, while in Explorers of Time and Darkness and Sky, they can only be found in Destiny Tower or Final Maze. They play a particular role in Red and Blue Rescue Team, where the player must either have a specific HM in the Toolbox or have a party member that knows the move taught by that HM in order to access certain dungeons.
In , HMs are treated more or less the same as TMs. Like TMs, they can only be used once and have the same bag sprite as TMs. Despite this, when a HM is dropped in a dungeon, the color of the HM differs from that of a TM.
====Appearance====
 	 	 	 	
Sprite of HM from	Sprite of HM from	Sprite of HM from	Unused sprite of HM from	Unused sprite of rainbow HMfrom
 	 	
Model of a HM from	Model of a HM from	Unused model of a Used HM from
==In animation==
===Pokémon Origins===
 appeared in File 2: Cubone. Much like in , it was given to by the captain of the S.S. Anne after helping him recover from his seasickness.
==In the manga==
===Pokémon Adventures===
========
In What a Dragonite, was revealed to have already obtained for his Ivysaur, for his Snorlax, and for his Pikachu, one of which he had won in a bike race in Wake Up—You're Snorlax!. When he tried to get his hands on , he ran into some trouble with a wild , eventually leading to the Hidden Machine getting destroyed. To help him, Misty gave Red her Gyarados in exchange for his , since it already knew Surf.
It was also revealed that had found HM03 before Red, fueling the young Trainer's determination of finding it too.
===Pokémon Zensho===
In Vermilion City, after defeating Lt. Surge, received the HM for Cut from the captain of the S.S. Anne, whom he had met earlier.
==Trivia==
* In the core series, and all Generation IV games have the highest number of HMs available (each game has eight HMs), and all Generation IV games have the most HMs required for completion (with six HMs required in each).
* Of all the core series games with available HMs, the Generation I games and the Kalos (Generation VI) games are the ones with lowest number of HMs (they have five HMs), and are the ones with fewest HMs required for completion (with only Cut needed).
* Flash and Defog are never required to finish a game. Flash and Defog remove obstacles (darkness and fog, respectively) that make it difficult to see; areas affected can still otherwise be normally explored with these obstacles present.
* With the exception of Flash, Fly, and Defog, all HMs are required to finish the games where they first gained their HM status.
* In the core series, the only methods that can remove an HM move are Move Deleter and the Pokémon Day Care. However, HM moves can be replaced as normal in games in which they are not HMs.
* The only then-current HM moves that were also able to be learned by Pokémon by level-up were and . Former HMs , , , , , and are also learnable by level, but only since their loss of HM status. Moves that regained their HM status, like Whirlpool and Dive, remained learnable by level-up. Waterfall remains the only HM move that has been learnable by level-up since it was introduced as a move, prior to gaining HM status.
* is the only HM with a unique type. All other HM moves share their type with at least one other HM move.
** HM moves have so far been only of the , , , and types.
* As of Pokémon Brilliant Diamond and Shining Pearl, all HM moves have been available by TM at some point.
* In , on , Swimmer Lori states " is no longer the only HM move you use in water" when she is defeated. This is a reference to Generation I, where the only HM usable in the water was Surf.
* In Generation IV, all moves that were at one time an HM can be taught via some method, with Flash being available by TM70 and Dive being available by Move Tutor. Defog and Whirlpool, which replace each other in the Sinnoh- and Johto-based games, are both HM05.
** Generation IV is the only generation in which two moves share the same HM number.
* is the only HM in Generation V that is not found in a different location between and .
* In , , Kylie and Ashlyn, two Kalosian HM-makers encountered at Poni Breaker Coast during the post-game, explain that HMs are not only difficult to make, they also cannot legally be sold for money in most regions.
* Tracey's Scyther is the first Pokémon belonging to a main character of the to have used a then-current HM move, . It wasn't until that one of 's Pokémon used a then-current HM move; Ash's Grotle used .
** Although debatable, other Pokémon may have used and throughout the animated series; however, they were not directly ordered to use the move.
==In other languages==
HM move / Hidden move
==Notes==
==References==
==Related articles==
* TM
* TR
* Appendix:Fan terminology → HM mule
* Field move
* Poké Ride
* Secret Technique
Category:Games
Category:Equipment
*
Category:Terminology
Category:Pokémon Mystery Dungeon items
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