AYER — Before any advertising or announcement, Osawa Japanese Restaurant is already popular due to word of mouth.

Quietly opening on June 12, the new restaurant is building a loyal group of patrons and not just from Ayer. A more raucous, grander ceremony, complete with ribbon cutting and other pomp, has not been scheduled yet. But proprietor Ken Huang is not waiting for any ceremony to launch his lunch and dinner menus. The Chinese immigrant is ready now to serve his Japanese and Thai cuisine to Americans.

This is Huang’s fourth culinary enterprise. After finding success in Leominster, Ashburnham and Gardner with restaurants featuring similar fusion type fare, Huang set his sights on expansion. The three other businesses — all bearing in their name some incantation of the word Osawa, a city in Japan — remain open and still very popular.

Huang had never tried sushi or sashimi until he came to America.

“First of all,” he said, “I am from China and it is not very popular there. It is a dish from Japan that I first tried while living in Everett 15 years ago. “Now I love it. Interest in it is really growing here in America.” There are now more than 4,000 sushi restaurants in the United States.

Huang is using his 14 years of experience, across all aspects of restauration, to benefit from the surge in cultural embrace of sushi. “The time is right,” he said. “In our other place in Gardner, Sawa, we had a buffet before switching over to a conventional fusion type menu that includes Japanese, Thai, Korean and Chinese food. But we wanted a more limited menu that we could become specialists in. Our customers there kept asking for sushi and sashimi but we didn’t offer it.” So the new Osawa offers only Japanese food with some spicy Thai soups to round out the menu.

He bought the building at 9 Main St. in November 2016. And after a year of total gutting and rehabilitation, his Osawa rose from the rubble. The 5,000-square-foot dining area has 150 seats and a 45-foot-long bar, which is adjacent to the 30 feet of sushi bar. The all-wood interior is modestly adorned with earthy accoutrements like tree limbs and pebbles.

Everything about it is new, including an experienced crew of sushi chefs and wait staff. A veteran sushi chef, Qiang, heads a hand-picked collection of professionals who specialize in Japanese cuisine. Especially new is the list of hungry customers who arrived immediately after the doors first opened.

One patron, Brian LeBlanc of Groton, agrees. “It’s been excellent,” he said. “There is no other place for sushi around here.”

Another attribute that Huang likes to promote about sushi, aside from the flavor, is that it appeals to the crowd of busy people. “It is a quick and convenient meal for people on the go. And it is very healthy, especially for overweight people like me,” he smiles. The married father-of-two splits his time between the established shop in Gardiner and his newest place in downtown Ayer, which has some unique, private seating areas scattered about the layout. The furnishing are as welcoming as the meals, which come in sizes for kids and generous portions for lunches and dinners.

“Business, so far, has been better than expected considering we haven’t even done any advertising yet,” said Huang. And the relationship to the area is reciprocal. Not only does the community seem to enjoy their new neighbors, but the employees, most of whom are newly migrated Chinese, seem to enjoy the quiet town. “The people here are very nice,” waitress LiLian Tang said.

It is important to note that, although sashimi is thinly sliced raw fish, most sushi contains no fish at all and is a rice-based dish. What defines sushi is its necessary component, vinegared rice that is best when consumed at its freshest. So don’t wait for a grand opening, your sushi is ready now.