All moves used by or against a Pokémon with this Ability cannot miss. It also allows Pokémon to be hit during the semi-invulnerable turn of Fly, Bounce, Dive, Dig, Shadow Force, Sky Drop, and Phantom Force. It does not bypass type immunities.
A Tatsugiri hidden inside a Dondozo's mouth via the Commander Ability is immune to the effects of No Guard.
In Diamond and Pearl, a Pokémon with No Guard can successfully hit a Pokémon that has used Protect or Detect, but only if it uses a move with less than 100% accuracy. The lower the initial accuracy of the move, the higher its chance of breaking through Protect or Detect. Thus, when used against Protect or Detect, moves that never miss (such as Swift and Aerial Ace) will always be blocked. One-hit knockout moves are exempted from this behavior and will be protected against. This battle mechanic was a bug, and was fixed in Platinum so that most moves are blocked by Protect and Detect.
Outside of battle
Outside of battle, if a Pokémon with No Guard is in the first place in the party (even if fainted), the wild Pokémon encounter rate increases by 100%. It shares this property with Arena Trap and Illuminate.
In Pokémon Sword and Shield, this Ability only affects the rate at which random encounters happen.
In Pokémon Scarlet and Violet, this Ability has no effect outside of battle.
Pokémon Mystery Dungeon series
In the Pokémon Mystery Dungeon: Explorers series, No Guard causes the Pokémon to ignore both harmful and beneficial modifications to accuracy and evasiveness for both the target and itself. This prevents the Pokémon's own Concentrator and Clutch Performer IQ skills from working.
In Pokémon UNITE, No Guard is Honedge's and Doublade's Ability. It increases the damage dealt and received by the user. After evolving into Aegislash, it becomes Stance Change.
||Allows Pokémon to ignore stat modifications to accuracy and evasion.
||Allows Pokémon to ignore stat modifications to accuracy and evasiveness.
||めいちゅうと かいひの だんかいを むしする
||The hit rate of moves and attacks won't be lowered even if accuracy is lowered or evasiveness is boosted! It has the same effects on you as on your enemies. Abilities that boost evasiveness have no effects, either.
||When changes to the Pokémon's and its target's accuracy or evasiveness make it more difficult for attacks to land, those changes go away so that the Pokémon can have a fair fight.