Turnback Cave: How to Catch Giratina

Prepare for Turnback Cave: Bring a Pokémon that knows Soak to change Giratina's type from Ghost to Water, making it vulnerable to False Swipe. High-level Octillery (Fountainspring Cave), or Golduck/Seaking (Sendoff Spring) can learn Soak. Also, obtain a Shedinja by training a Nincada to level up with an empty party slot.

Navigate Turnback Cave: Use Defog to clear the fog. The cave has random rooms with four doorways. Entering a new doorway leads to a random room. Your goal is to find 3 'pillar rooms' within 30 total rooms entered.

Finding Pillar Rooms: Pillar rooms have a central pillar with a plaque. 'Filler rooms' have cracked rocks. If you enter more than 30 rooms, you must restart. If you enter a doorway you just came from, you'll also be sent back to the entrance.

Reach Giratina: Once you find the 3rd pillar room within the 30-room limit, the next room you enter will be Giratina's chamber.

Battle and Catch Giratina: Giratina is Level 70 in its Altered Forme. Use Soak on Giratina to change its type to Water. Then, use False Swipe to lower its HP. Shedinja is highly effective due to its immunity to Giratina's Dragon Claw and Aura Sphere via Wonder Guard. If Giratina uses Shadow Force, swap to a Normal-type to absorb the hit. For Pain Split, field Shedinja, as its 1 HP will cause Giratina to lose half its HP when it uses the move. Apply status conditions like paralysis, then throw Poké Balls to catch it.