Sturdy

Sturdy serves as a crucial defensive ability that provides two distinct forms of protection in battle. When a Pokemon with Sturdy is at full HP, any attack that would normally result in a knockout will instead leave the Pokemon with exactly 1 HP, effectively guaranteeing survival from the first potentially lethal hit. Additionally, regardless of the Pokemon's current HP status, Sturdy grants complete immunity to one-hit KO moves including Fissure, Guillotine, Horn Drill, and Sheer Cold, making it impossible for these moves to connect successfully.

The ability underwent significant enhancement between generations, originally only protecting against OHKO moves in Generation 3 before gaining its signature "survive with 1 HP" mechanic in Generation 5. An important interaction occurs when a Sturdy Pokemon holds a Focus Sash - the ability takes priority over the item, meaning the Focus Sash will not be consumed when Sturdy activates, preserving it for potential future use.

Competitively, Sturdy has proven valuable on Pokemon like Magnezone and Aggron, allowing them to guarantee at least one turn of setup or retaliation even against overwhelmingly powerful attacks. Steel-types particularly benefit from this ability, as their natural bulk combined with Sturdy's protection creates formidable defensive cores. The ability enables reliable leads that can set entry hazards or revenge killers that can guarantee their attack before fainting, making it a strategically significant ability in both singles and doubles formats.