I didn't read through the chit-chat reply scrolls here, so maybe I am echoing another user's thoughts.
I would stay away from Tinder, Badoo, Coffee n Bagel, and other foreign apps. They are pretty much garbage, and probably even more useless for us Asian Americans. Some have success on those and glad they are having fun, considering if it is even real. The girls or women(age?) in Tokyo are usually not of good quality.
There are 2 ways to pick up non-working girls here in Tokyo. You pay via sugar dating or you do the footwork and get out on the streets to introduce yourself, sales - old school lobby lizard style. Others will say otherwise but for your short trip to Japan, stick with this advice.
I can tell you that there are plenty of Japanese girls who prefer an Asian American guy to the other vanilla and choco flavors. But you need at least a few months to build the interest and get dates. Once you are on the date, then it is up to your skills to close the deal. Once you are on the date and you mess it up, then you deserve to go back to your hotel alone.
Next advice, do NOT join the Nampa group fools. Talk about sausage and nerd and uncle fester fest. The girls you want to meet don't want anything to do with those so called creatures. I have had a few girls post me pics of those idiots and it is truly sad. Don't be those guys.
You need to treat it like a job search. Put your best profile forward, in Japanese if possible, and wear something nice and for pete's sake, brush your teeth and gargle with minty listerine.
Next, you want to get at least 10 girls interested and actual meeting dates, agreed on terms and conditions. 10 girls will probably dwindle down to 1-2 girls. You are looking for a connection, which will lead to a quick move to the love hotel or your hotel room. Those guys who are saying they transitioned the girl from the hotel bar on the first night should really get an STD or HIV check because, that's why.
I hope you have an enjoyable time here in Tokyo. All this being said, I think you would be happy visiting Angeles or Pattaya to get the deed done many times over.....
Have fun!