What papers do I need to enter Japan?

Hi, I can extend my layover and stay in Japan for a week, I was wondering what kind of papers I would need to enter the country. I�fm a US resident with all my papers but is a Vietnamese citizen. I do not have a Vietnamese passport but can get one within a month. Thank you for your help.

Visa.

If you are holding a US passport then you are good for under 90 days. Refer to https://www.us-passport-service-guide.com/japan-entry-requirements.htm...
If you hold a Vietnamese passport then check their website for details.

You do not say what passport you are travelling on. That dictates what you need.
Refer to the official source - it's pretty simple to follow.
https://www.mofa.go.jp/j_info/visit/visa/index.html

Hi, I�fm flying to Vietnam from Los angles. I do not have a passport, but I am able to get a Vietnamese passport. I have a layover in Tokyo, I�fm able to extend the layover for a week. I was wondering with a Vietnamese passport do I just need a visa ? Thank you

You�fll need for sure a passport to go from the US to Vietnam. So get one quickly. For Japan you�fll then need to apply for a visa on you Vietnamese passport.

Let's try this one again.

Your first question should be "what papers do I need to show the airline to get on an international flight?

It is possible you have some other kind of travel document, but for 99.999% of people, without a passport you are not going anywhere.