From the moment he steps off the plane onto this new continent he immediately encounters the legendary Pokemon Zekrom whose attack cause Ash’s Pikachu to become severely weakened in strength (unable to do electric attacks for a certain period of time). From right at that moment we know that things are going to change with this series.In the past whenever Ash journeyed to a new region his Pikachu is mysteriously weaker than it was in the previous season.

This was a major inconsistency that left a lot of viewers feeling that the series was simply recycling the same plot every time a new season begins and they weren’t wrong. But with Black and White from the get go we are given a reason for why Pikachu is substantially weaker than before (it is necessary for Pikachu to be weaker in order for Ash to still have a challenge in this new region afterall).