>>44807057It's less of a rule and more of a guideline. Numerous pokemon are depicted as using more than 4 moves but the recent anime generally tries to keep it down to 4. Pikachu 'forgetting' Volt Tackle for Electro Ball and then Electroweb is more or less just the anime depicting move learning to its child audience. Personally, I view it as an evolution of moves.
>Volt Tackle is raw electrical power built up with speed>Electro Ball is concentrated electrical power in the tail that scales on speed with limited application>Electroweb is a complex move with a wide variety of advanced applications formed from Pikachu's tail like Electro BallSo essentially, Electroweb seems more or less like it could be a heavily refined Electro Ball which is a concentrated Volt Tackle. There are other things like how Leon trains his Charizard in a wide variety of moves despite TMs not really being a thing (to my memory) but that could just reflect Leon's skill as a trainer rather than his Charizard being capable of more than 4 moves.
