How do you catch a shiny Giratina?

Answer 1

When you meet Giratina in the Distortion World or Turnback Cave (in Pokemon Diamond and Pearl), you will need to save before you encounter it into battle. In battle, there's many chances that the Giratina will not appear shiny as you hoped it will be. Soft reset (L+R+Start+Select anytime) and start the game up again, repeating the same process. There's only 1/8192 chance of it appearing as a shiny, so be patient as you repeatedly soft reset. It is recommended that you have a Master Ball with you to guarantee its catch, but it isn't impossible to do it with a regular Pokeball. Bring a level 50-70 (Depending on where you meet Giratina, for in Platinum it'll be level 47, while in Diamond and Pearl it'll be level 70.) Pokemon that will cause Giratina to fall asleep or paralyzed. Bring its HP down to yellow or red, then chuck a Dusk Ball or Ultra Ball to attempt a good catch.