Having a critical hit land is a major game-changing factor. Like EVs and EV training, a critical hit is another game mechanic overlooked by many. Don’t worry, I’ll explain it entirely. First of all, you notice critical hits do more in a battle (mainly because of the message “A critical hit!”). That’s because they deal 2 times the regular damage, without computing Same Type Attack Bonus (STAB) or type matchups. If the right items and moves are used, critical hits can be used to take out fast-moving, powerful Pokemon in battle. A chance of getting a critical hit is divided into five stages, each having a higher percentage than the other.
Most moves fall into Stage 1, which is the default probability of 6.25%, or 1/16. If you look closely into a move description, though, you can see if the critical hit ratio will increase to Stage 2, which is 12.5%, or 1/8. Moves like Slash or Razor Leaf say that they have a high critical hit ratio; this puts them into Stage 2 automatically. (For some reason, Frost Breath and Storm Throw always result in critical hits, but are placed on the Stage 2 list). Items can also be used to increase the chance of landing a critical hit.
One of the most common items is the Scope Lens, which increases the probability of critical hits by one stage. Just so you know, Stage 3 is 25%, or 1/4, Stage 4 is 33.3%, or 1/3, and Stage 5 is 50%, making critical hits very likely to occur in battles. The Scope Lens can help you deal more damage without changing your stats. You could even deal as much damage as an EV trained Pokemon of the same species if you play your cards right. Focus Energy will increase the critical hit ratio one stage, but this can be only used once. (To tell you the truth, I’m not sure why it has 30 PP.)
For specific Pokemon, you can get their critical hit ratio up to Stage 5. If you have a Chansey, you can have it hold the Lucky Punch, which is a hold item specific to Chanseys. It will raise the critical hit ratio by two levels. The same applies to Farfetch’d: its hold item is its Stick, which in the Pokedex, says it can’t live without. Yes, you’ve done the math, and you can conclude that the critical hit ratio will be only at Stage 4 (considering you have a Stage 2 move). This is where ability comes into play. The ability Super Luck will double the critical hit ratio to a maximum of five, getting you to Stage 5.
However, not all Pokemon will have this ability; the only known Pokemon to have it are Murkrow, Honchkrow, its evolved form, and Absol (its second ability being Pressure). You have to make sure it can learn one of the Stage 2 moves; the list can be found in Serebii (type in critical hit in the search bar). Even though this has nothing to do with stages, the ability Sniper will make critical hits deal 300% damage instead of 200%, which can one-shot most Pokemon easily. This ability is limited to but a few Pokemon as well. I hope you can take this advice about Critical Hits, and implement it in your future battle strategies.