I pushed the fabric aside and opened the thick and heavy wood door wide enough to slip in. I had walked into a semi-lively, softly lit Japanese restaurant with a medium-sized sushi counter (probably sat 8-10 people at most?). A shallow bamboo basket with the offerings of the day (prepared slabs of fish, various cleaned shellfish), ready to be made into sushi and sashimi, resting on the corner and visible when you walked in. A few Japanese families with their kids and babies and other parties of two or four filled the tables. Everyone but me is speaking Japanese including the only non-Asians in the entire place, a visiting Peruvian couple that apparently lived in Japan for several years for work, chatting away with the sushi chef/owner at the counter (yours truly can't speak a lick of proper nihongo). Fortunately the waitresses spoke the local language. They greeted me, sat me at the counter, and helped me figure out my order (many pieces of nigiri sushi and a few hot dishes). The owner also spoke the local language and was very welcoming and friendly. One of the best meals of my life, and while it certainly wasn't cheap (could have bought a few weeks' of groceries instead), it felt really special being there.
In hindsight, walking into unmarked store at night was a risky move, especially with a door that thick. Fortunately it worked out that time.