How do you get light ball from Pikachu?

Answer 1

You can either catch the Pokemon, use the move thief on a pikachu that has one, but make sure that Pokemon isn't holding anything, or else it will fail. I think that the move trick switchs items that the Pokemon is holding, and your Pokemon does not need to be holding an item. However, only like 10% of the pikachus you battle will be holding the said item, so in other words, it is rare. To tell the truth, I don't know if 10% is the right percentage, but I know it is low, so look forward to a long time of stealing items from pikachu, most of them are holding berries. On the plus side, you'll get alot of berries.

The easiest way to get a light ball is to trade a Pikachu over from then yellow version. When he is traded over he has the light ball in his equipment

there is no easy way well i dont know if the yellow pikachu has but if you want one with light ball there is a 5% to catch it with the item