Japan Visa Long Term

Hello Everyone,

I am Mao and I am currently doing research on what kind of visa should I acquire if I am planning to stay and work in Japan?

I am Half Japanese and was recognized in my father's koseki tohon. Though unfortunately my father has already passed away.
I am now 24 years old.

A few facts I got from my research and inquiring thru agency are:
-I can apply for a Child of Japanese National Visa despite my age
-The Child of Japanese National Visa allows me to work fulltime in Japan.
-if I want to get a Japanese Nationality I must undergo naturalization.

But my question is,
If I am elligable for Child of a japanese national, what are the other documents I would need to apply for such visa?
Currently, I have my late dad's koseki tohon.
What procedure and measures should I take to not get rejected for a visa?

When I was 16 I tried to apply for a visa but since my mom served as my guardian because I am minor, our visa got denied because my mom had deportation records in Japan.

I will be applying alone this time. So I am researching for the best way to get a visa to japan.

And last question, since my dad has already passed and if a letter of a guarantor/invitation is needed. Will it be okay if my cousin who is now a Japanese citizen be the one to provide me this documents?

Thank you. I look forward to your help.

Ask the embassy where you will be applying for a visa. If they say you need a CoE first, see here: http://www.immi-moj.go.jp/english/tetuduki/kanri/shyorui/01.html

You don't need a COE, you can apply directly to the Japanese embassy or consulate for the visa.

The thing is we went to the Japan Embassy here and they told us that they have a strict policy of only accepting visa application thru an accredited agency. So we did go to an accredited agency. The Agency told us that we need a Certificate of Eligibility to have good chances of Obtaining a Visa.