Note that "N2" is Level 2 of the Japanese Language Proficiency Test, which is the 2nd highest level of 5 and entails multiple years of study.

You can pass N2 in one year of full time study (if you apply yourself). The multiple years tend to be when people are trying to pass it doing part time study.

True, though for reference that's only 10 of the points. Hitting 10M yen is 40 and a master's is 20.

It always seems strange to me how much deference is given to masters degrees for immigration purposes when in many industries they aren't worth getting, and can actually correlate negatively with someone's skill. And you get no points for a "mere" undergrad degree, even though in many fields such as CS that's more meaningful as it represents twice as much work. At my alma mater, the undergrad CS holders are much more capable than the graduate CS holders on average, simply because the undergrads know they don't need the grad degree and thus don't get one, whereas the grad students had a different undergrad degree and may have only gotten those two years' worth of exposure to CS. So the undergrads have twice the experience, which is substantial. This phenomenon is widespread in CS.

10M yen+

For reference, believe that's ~ USD$91k, EUR€82k, GBP£72k.