Unless you already know about this tiny San Gabriel gem, you might drive right by it and never know it’s there.

But once you do find the entrance through a back door at the end of a parking lot and walk into the tiny market, you’ll have found one of the San Gabriel Valley’s best-kept secrets and a place where regular customers say the best sushi in town is served, just not on tables or at a sushi bar, but in to-go boxes.

“I first heard about this place years ago from a friend who gave me some of their sushi and I loved it. We love the freshness of their products — the sushi, the fish is the best,” said Theresa Lin, a longtime customer at Yama Sushi Marketplace, a mini-market on Las Tunas Drive that is celebrating 40 years in business.

At first glance the market looks, well, just like a little mom and pop market. It’s maybe half the size of a typical 7-Eleven and it sells all sorts of Japanese and other Asian products like chips, candy, sweets, juices and sauces. But locals know it as the place to go for high-end restaurant style sushi and sashimi in a box.

“From the front it looks like we’re closed. You can only come in through the back so it’s kind of like a speakeasy for fish. And a lot of our regular customers want to keep it a secret and don’t want to tell anyone because the line on the weekends is like an hour long to get all your sushi and sashimi,” said Scott Kohno, who purchased the market from the original owner about three years ago.

The marketplace was opened in the summer of 1984 by Kenzo Yamada and his wife, Nobuko, as Yama Seafood. Yamada was a fish broker selling to fancy restaurants in Los Angeles. According to Kohno, the plan with the market was to sell fresh fish directly to San Gabriel Valley locals instead of restaurants.

“Because of his background in the fish business he had the prime fish like salmon and tuna that the fish companies would give him because he knew them all,” he added.

A few years later, as sushi was becoming more popular, Yamada decided to switch things up and start selling sushi and fresh cuts of salmon, ahi tuna, yellowtail and bluefin tuna sashimi that he would personally slice, which often meant there were long lines of customers waiting for their cuts.

Today General Manager Enrique “Kike” Moreno, who’s been there since the beginning 40 years ago, runs the small kitchen where sushi like spicy tuna and other rolls, as well as salmon, tuna and yellowtail nigiri, are made every hour and sold in to-go boxes from a display refrigerator. At the sashimi counter, thick slices of ahi, salmon and other high-end fish are for sale.

Surprisingly the star of the market is the California roll, which most sushi connoisseurs would consider a “starter” selection.

“It took me a long time to develop the recipe and I guess it’s about the exact portions of the ingredients. It has exactly the right portions so you can taste everything,” said Moreno, who noted that the store takes care to get the right balance, from the type of imitation crab used to the perfect crunchiness of the cucumber to the ripeness of the avocado to the right mix of mayo. The roll, which was created 20 years ago, is also about twice the size of a typical California roll.

“This became the star. It’s creamier and we sell hundreds every day,” Kohno said.

Yama Sushi Marketplace is expanding as well. A second location opened in 2022 in West L.A. at 11709 National Blvd., where sushi-making classes are also offered. A third location in Koreatown is set to open in September.

Kohno knew that when he took over the original store he was taking on a huge responsibility to keep a local gem going.

“We have to carry on this tradition,” he said.

And for Moreno, the marketplace has become an essential part of the community.

“There are a lot of customers who have been coming for 30, 40 years, and we got generations of customers coming now,” Moreno said.

Yama Sushi Marketplace is at 911 W. Las Tunas Drive, San Gabriel. More info is at 626-250-6203 or yamasushimarketplace.com.