Is it possible to have US/Japan dual citizenship?
The advantage of both is being able to live/work without visas because you are a citizen. That when you arrive at the international airport, you can stand in the local citizen line as they tend to be shorter than foreign citizen line. To get a Japanese green card/citizenship is much harder. I’ve known half-Japanese who married Japanese and lived in Japan who got rejected. So let’s say you gave up Japanese citizenship but then wanted to live there and work. Or had a family emergency and needed to stay there for longer than a tourist visa allowed. You might have difficulty. But I’ve also known a Japanese citizen by birth who lost it because they grew up abroad, who went back to Japan and was able to get a work visa. South Americans have it easier in this respect as there is a working visa program for the Nikkei there.
The US does not care if you have multiple citizenships. It’s perfectly allowed, with but one restriction: if you hold US citizenship, US authorities will not recognize the fact that you have any other citizenship besides American; what that means is that they will consider you an American in all cases and your other citizenships will be ignored completely. One of the consequences of that is that, when traveling and returning to the US, you are required by law to present proof of your US citizenship, such as a passport. So if you had a US and a Japanese passport in your pocket and you came up to the immigration officer, you would be required to present your US passport. But as far as the US government is concerned, you can have American and Japanese citizenships. Your problem is with the Japanese side. Now as far as Japanese citizenship goes, the law is a little unusual. Typically, if you have a non-Japanese citizenship and have a claim to Japanese citizenship, you are required by Japan
If you are Japanese the US will expect you to give up your citizenship when you naturalize but won’t check to make sure you do. If you are American it’s much harder to get Japanese citizenship. My father in law, the American born son of two Japanese parents was refused Japanese citizenship. His children have also been refused citizenship. The disadvantage is that you may have difficulty getting consular support when traveling as both countries may decide it’s the other countries responsibility. Another disadvantage is if you have US citizenship you must file tax returns here no matter where in the world you live. The only real positive is that you can travel between the two countries without waiting on the non citizen line at immigration.
