These tricks are errors (bugs) from Pokémon Diamond and Pearl Japanese version, use them at your own risk, you could lose the game save.
If you do them well, you will get the legendary catches that are only from Nintendo Events in Japan.
Getting Shaymin
First go to the Pokémon League, enter and when you're in the same room as the first opponent, use Surf on the door you just entered.
Walk a step down and reset the step counter (leave it visible in the bottom screen) .
You must walk exactly 200 steps to the right from the door.
Then you can use the bike to get there faster, but be careful not to go further.
Walk 363 steps down (563 steps total).
Then 722 steps to the right (1285 steps total).
And finally 19 steps to the left (1304 steps total).
Use the Underground Kit
You should appear in the subway, just come back.
You should now appear on a road in the middle of the sea with white ground, is normal, the textures of the game have not been charged.
Walk 3 steps up, check the backpack and go back (you don't need to look at the map) .
If you followed the instructions well, you're on a road made of flowers in the middle of the sea.
Go North for a while, at the end you will see Shaymin (level 30)
Once you defeat it or catch, get out of there by flight, as it is the only way to return.
Get Darkrai
Again we need to surf, but this time the flight is not required.
This time, choose to have visible the map on the bottom screen, since it is more important than the steps we take.
Well, do Surf Like last time, but this time we go to the other door.
Go up until you change route 5 times.
We try to go underground, it will give us a blue screen, don't care, restart the game.
We will be right where we dug, we go now down all we can until we get blocked with an invisible wall.
When this happens, step up 2 and 15 to the left and then move down (you can use the bike).
We must be paying attention to the map, we will be now at the top left corner of it, so we must go down to see that we are in the upper left corner of the island of the full moon, now check out the backpack, you'll see the sea on your right , go until you are 2 steps away from it, go to underground and then back, then move to the right, you will see that the sea disappeared, when it reappears stay at the seaside and go down, you will see the island of the moon but we don't want to go there, so go down until you see a darker area, then get into it and continue to the right, you will enter a zone with sea around, and later it will become a dark zone again, once this occurs walk up a little and there you will have the island of Darkrai.

Climb the stairs and save the game.
Restart the game and you will see you've really finished in a dark place, do not be afraid, check the backpack, everything will be normal again.
Now move a little and into the woods to see Darkrai (Level 40) . It is a really hard to catch Pokémon and gives you many headaches, so be patient.
Once trapped, or weakened, you can leave the island by boat, since it's not allowed to fly.
In case you want to see Cresselia, repeat the process but stop at its island, the rest is exactly the same (remember that when you talk to this Pokémon, it flees).










