Counter

Counter is a Fighting-type move introduced in Generation 1.

Values by generation

From PokeAPI's change history. Up to Generation 3, physical or special depends on the type. Highlighted cells changed from the previous generation.

Generation	Type	Category	Power	Accuracy	PP	Priority
Generation 1	Fighting	Physical	—	100	20	-5
Generation 2	Fighting	Physical	—	100	20	-5
Generation 3	Fighting	Physical	—	100	20	-5
Generation 4	Fighting	Physical	—	100	20	-5
Generation 5	Fighting	Physical	—	100	20	-5
Generation 6	Fighting	Physical	—	100	20	-5
Generation 7	Fighting	Physical	—	100	20	-5
Generation 8	Fighting	Physical	—	100	20	-5
Generation 9	Fighting	Physical	—	100	20	-5

Gold / Silver · Crystal	Returns a physical blow double.
Ruby / Sapphire · Emerald	Retaliates any physical hit with double the power.
FireRed / LeafGreen	A retaliation move that counters any physical hit with double the damage.
Diamond / Pearl · Platinum · HeartGold / SoulSilver · Black / White · Black 2 / White 2 · X / Y · Omega Ruby / Alpha Sapphire · Sun / Moon · Ultra Sun / Ultra Moon · Let’s Go, Pikachu! / Let’s Go, Eevee! · Sword / Shield · Legends: Arceus	A retaliation move that counters any physical attack, inflicting double the damage taken.
Scarlet / Violet	A retaliatory attack that counters any physical move, inflicting double the damage taken.

Red / Green · Blue · Red / Blue · Yellow	TM18

All versions combined; see each Pokémon's page for game-by-game details.

Sources : PokeAPI (moves, move_changelog, move_flavor_text, pokemon_moves, machines)