**In Generation V**, there is **a chance of a critical capture**, where the Poké Ball will only shake on the ground once before capture. When a critical capture occurs, the Poké Ball will make a high-pitched whistling sound as it is thrown, then pause in mid-air, and shudder before it drops down to the ground.

The probability of a critical capture depends of the number of Pokémon that has previously been caught in the Pokédex. First, compute the value of a (the modified catch rate), as above. Then, whether or not this value is less than 255 (above which the Pokémon is caught regardless of whether or not it is a critical capture), multiply this value by the following:

Species Caught Multiplier

600 2.5

451-600 2

301-450 1.5

151-300 1

31-150 0.5

<30 0

**A random number is generated, and if it is less than the modified value, a critical capture occurs.**

Critical captures make one shake check instead of three, thus it appears to increase the odds of capture for Pokémon. Though it may create higher odds of capture, a critical capture is not a guaranteed catch; it is possible for critical captures to fail. For example, a critical capture against a full-health Pokémon with a catch rate of 3 (such as Kyurem) with a Poké Ball will still only have a 25.03% chance of success, but it is much higher compared to the normal capture's 1.57% chance. Furthermore, situations where critical capture is guaranteed will not guarantee capture.

- **Bulbapedia**

*Hope I Helped! :)*