I have a slightly different take on this reading.
You may have heard that in Japanese when counting objects, you use a special ‘counter’ word depending on the type of object. にん is the counter word for people. Three people, four people, how many people all use にん. Unfortunately to make it harder, there is a special counter word for one person and two people.
Equally confusing, にん is sometimes used as the reading for this kanji even when you are not counting people. I don’t have an explanation for that and it could be that I’m wrong about にん being a counter word. If anyone with more knowledge than me has an explanation for this I’d be happy to be corrected.



