Pokemon Gold and Silver - Critical Hits

A Critical Hit is based on value n and a random number. If the random number is less than n, then the attack is a Critical Hit. Here is how n is decided.

1. If the attacker is Chansey equipped with Lucky Punch, n=2. If the attacker is Farfetch'd equipped with Stick, n=2. If neither is true, n=0.
2. If Focus Energy is in effect for the attacker, then add 1 to n.
3. If the attack is Karate Chop/Razor Leaf/Crab Hammer/Slash/Aero Blast/Cross Chop, then add 2 to n.(Add 0 to n for any other attacks.)
4. If Scope Lens is equipped, add 1 to n.

After determining n, you'll get a Critical Hit (CH) number:

n	CH Number
0	17
1	32
2	64
3	85
4	128

n can have a maximum of 4.

If the random number is less than the CH Number, then the attack is a Critical Hit.