In chapter 367 (episode 257), Luffy asked what 2 x 108. Zoro answered 216. Luffy decided on 300 as the number of LuffyZoro attack, Canon.
Why the number 108 of all number? I gave it a thought and...
108 is the number of Urouge's bounty.
2 is the number of the time-skip.
I can say to a certain...