I discovered an anomaly when I searched the Psydex for information about a Pokemon I just captured in my Pokemon Black game: Deino, whom I plan to evolve into Hydreigon. The move Dark Pulse is listed as an egg move for Hydreigon, but according to the Psydex, no compatible Pokemon can learn the move by level-up, move tutor, TM or egg move. Very odd!

Apparently, the secret to these egg moves lies in past generations of Pokemon games.

HOW TO TEACH THE EGG MOVE "DARK PULSE" TO YOUR HYDREIGON
1) First, you need a Generation IV game (preferably HeartGold or SoulSilver) and the TM for Dark Pulse, which is not found in Gen V.
2) Capture a male Gyarados in your Gen IV game, and use the TM to teach him Dark Pulse.
3) Import Gyarados to your Black or White game using the PokeShifter, then go to Victory Road in Unova and capture a female Deino.
4) When you have Deino, breed her with your Dark Pulse Gyarados to produce an egg, which will hatch into a baby Deino who knows Dark Pulse. This is the only way of getting a Deino (and eventually a Hydreigon) to learn this move.

In the Psydex, when you come across egg moves which no compatible Pokemon can apparently learn, try looking up the move in the TechDex and see if you can find a compatible Pokemon that could only learn the move in earlier games, either by TM or by a move tutor. It seems that these egg moves can only be made possible by Pokemon crossing over generations.



--- FULL LIST OF INTERGENERATIONAL EGG MOVES ---
It'd be too confusing if I listed all the evolutions, so I'll just list the first one for each Pokemon.
If the first evolutionary stage can learn the move, all the following stages can learn it as well.
An asterisk * means that other Pokemon in this evolutionary line can NOT learn the move.


AVALANCHE
> Gen IV Parents (TM72):
(Water 1 group)
Blastoise*, Crawdaunt*, Dewgong*, Empoleon*, Feraligatr*, Lapras, Slowbro/Slowking*, Walrein*
(Water 3 group) Cloyster*, Crawdaunt*
>> Teach move in Gen IV, then import to Gen V and breed

CAPTIVATE
> Gen IV Parents (TM78):
(Humanshape group)
Abra, Buneary, Cacnea, Chimchar, Croagunk, Drowzee, Electabuzz, Makuhita, Hitmonlee/Hitmonchan/Hitmontop, Jynx, Lucario, Magmar, Meditite, Mr. Mime, Sableye, Spinda, Volbeat
>> Teach move in Gen IV, then import to Gen V and breed

FOCUS PUNCH
> Gen IV Parents (TM01):
(Mineral group) Sudowoodo, Geodude
>> Teach move in Gen IV, then import to Gen V and breed

GIGA DRAIN
> Gen IV Parents (TM19):
(Flying group) Natu, Zubat
>> Teach move in Gen IV, then import to Gen V and breed

IRON TAIL
> Gen IV Parents (TM23):
(Humanshape group) Abra, Buneary, Chimchar, Electabuzz, Lucario, Magmar
>> Teach move in Gen IV, then import to Gen V and breed

MEGA PUNCH
> Gen III Parents (Move Tutor):
(Mineral group) Sudowoodo, Geodude
>> Teach move in Gen III, then import to Gen IV
>>> Import to Gen V and then breed

SECRET POWER
> Gen IV Parents (TM43):
(Bug group)
Spinarak, Beautifly/Dustox*, Butterfree*, Beedrill*, Skorupi, Trapinch, Pineco, Gligar, Heracross, Volbeat, Ledyba, Surskit, Wormadam/Mothim*, Nincada, Paras, Pinsir, Scyther, Shuckle, Vespiquen*, Yanma, Venonat
(Plant group)
Snover, Chikorita, Bellsprout, Shroomish, Bulbasaur, Cacnea, Carnivine, Cherubi, Exeggcute, Turtwig, Hoppip, Lotad, Seedot, Paras, Roselia, Sunkern, Tangela, Tropius, Oddish
(Humanshape group)
Abra, Buneary, Cacnea, Chimchar, Croagunk, Electabuzz, Drowzee, Makuhita, Hitmonlee/Hitmonchan/Hitmontop, Jynx, Lucario, Magmar, Meditite, Mr. Mime, Sableye, Spinda, Volbeat
>> Teach move in Gen IV, then import to Gen V and breed

SKILL SWAP
> Gen IV Parents (TM48):
(Bug group) Butterfree*, Venonat, Wormadam/Mothim*
(Humanshape group) Abra, Drowzee, Jynx, Mr. Mime, Spinda
>> Teach move in Gen IV, then import to Gen V and breed

SLEEP TALK
> Gen III Parents (Emerald Move Tutor):
(Fairy group)
Marill, Shroomish, Clefairy, Skitty, Snubbull, Hoppip, Jigglypuff, Mawile, Plusle, Minun, Pikachu, Roselia, Togetic
> Gen IV Parents (TM82):
(Fairy group)
Marill, Shroomish, Cherubi, Clefairy, Skitty, Snubbull, Snorunt, Jigglypuff, Pachirisu, Hoppip, Plusle, Minun, Pikachu, Roselia, Togetic
>> Teach move in Gen IV, then import to Gen V and breed

STEALTH ROCK
> Gen IV Parents (TM76):
(Monster group) Cubone, Nidoking*, Rhyhorn, Larvitar, Aron, Turtwig, Gible, Shieldon
>> Teach move in Gen IV, then import to Gen V and breed

STEEL WING
> Gen IV Parents (TM47):
(Bug group) Vibrava/Flygon*, Gligar, Scyther, Yanma
>> Teach move in Gen IV, then import to Gen V and breed

EXTREMESPEED
> Gen IV Parents (Dragon's Den): Dratini
>> Receive ExtremeSpeed Dratini in HGSS and then import to Gen V
(Not technically an egg move, but its listing in the Psydex warrants an explanation)

VOLT TACKLE
> Gen IV Parents (Light Ball): Pikachu
>> Breed in Gen IV and then import to Gen V
(There is no Light Ball in Black/White, so Volt Tackle is not a possible egg move in Gen V)


...I have only covered Gen III and later in this guide, but there is also the occasional move that can only be inherited in GSC by trading in a parent from RBY.

You might notice that no Pokemon in the "Ground" egg group are mentioned here. This is because Smeargle's Sketch can copy any egg move, thus eliminating the need for trading across generations.

Thanks for that little tid bit. Im thinking a few other people saw that and had no idea how that was possible. HEck, I probably would'nt have figured that out!

Thanks for the information!

Maybe we should make a list, then you Edit your first post with the list?
Pokemon Name:
Attack Name:
Pokemon needed from Gen IV:
Method:

If I have some time I'll look for some, but I don't have anytime right now.

This works in gen4 as well, getting pokes to pass gen3 tutor moves. Such as Dewgong learning body slam in FRLG, taking it to HGSS and teaching it Aqua jet to get an Azumarril with both egg moves.

I think a new category of "Parents" should be added to the Psydex Egg Move information table (perhaps simply called "Other Parents") and the explanation of these moves can then be added to the "Possible Chain" dropdown box.

For Hydreigon's Dark Pulse, the chain would go:
> TM (Gen IV): Gyarados
>> Trade: Black/White
>>> Breed: Hydreigon

The problem is that the Psydex does not yet include an explanation of how these egg moves are learned, so when I have time I'll make a full list of intergenerational egg moves (for both Gen IV and Gen V Pokemon) and add it to my first post.

Thank you.

I'm not sure how to write the list, though.

I started to write it in Notepad, sorting the list by Pokemon (which is how I've been finding the moves in the Psydex) - but there's an awful lot of overlap caused by all those old TMs that no longer exist, and the Move Tutors in past games. There might be several Pokemon, in a variety of egg groups, that can learn a move like Secret Power... and the entire list has to be written out once for every Pokemon. I'm already fed up with this system, so I'll start again with another one.

I think what I'll do is sort the final list first by move, then by method.

...I also found one move that's actually impossible to legitimately inherit (Shellder can't learn Take Down in Gen III or later, except through cheating).
What I really should do is contact the Psypoke staff and ask that this problem be fixed properly.



EDIT: I have posted this issue in the Viridian Forest topic and received a reply from Jigglypuff. He says the Egg Move section of the Psydex needs to be reworked, and when that's finished, intergenerational egg moves will be included in the new version. But this will undoubtedly take a lot of time and effort, and there may not be a "quick fix" in the meantime.

So I'll resume work on my list, although that will take a fair bit of time as well. I'll edit my first post when the list is complete, and hopefully the topic will be stickied so it stays alive.

Similarly, if you want a Mach punch+Drain punch Conkeldurr:

>Male Hitmonchan (gen IV) level up for Mach punch
>>Teach it the Drain punch TM
>>>Breed with Conkeldurr (female)

I have gone through the Psydex entries for the first generation of Pokemon, and used it build a list of Pokemon egg moves that can only be obtained by trading. The guide is still a work-in-progress, and will take a while to complete - but it's got all the information I could find about intergenerational egg moves for the first 151 Pokemon, and there's a fair bit of data for other Pokemon as well.

(Note that I haven't included the moves that require trading from RBY to GSC. There are a couple of egg moves in GSC that have to be traded in from RBY - but I figure that now we have FRLG and HGSS, the first two generations are pretty much obsolete.)