How does one know when to use ～ふん or ～ぷん when telling time in Japanese?


I'm wondering if there are any linguistic reasons or rules that can be applied
to find out which to use, or do I just need to memorize them individually?




Well, all the Japanese counters have some irregularities. In this case, the
standard counter for minutes is ふん, but in some numbers it changes.

> 1: いっぷん 2: にふん 3: さんぷん 4: よんぷん 5: ごふん 6: ろっぷん 7: ななふん 8: はっぷん 9: きゅうふん 10:
> じゅっぷん

